Please
1. screenshot of your project when the video is on the timeline
2. screenshot of your ( customized) rendertemplate
for trying to help you.

Thank you

Here's the screenshot
1080p 60fps
Project Settings Rendering Settings
I know it is a bit 'unusual as the quality 1440x1080, but some time ago I started to try this setting for 1080p video and the result was Excellent! Now for some reason the quality has reduced to this:
Rendering
Original
As you can see, the rendering is much more pixelated. (Original video 40.000 bitrate - Rendered video 14.000 bitrate). As mentioned before, until a few weeks ago, with the same settings, the video came out perfect, and now this comes out.

Now I'm also trying these settings (1440p) to have the VP9 codec on Youtube, but the result is the same, the video always comes out pixelated:
Project Settings Rendering Settings

I really need help, this problem is destroying all the jobs and it doesn't make me want to continue ... and I love making videos!

I did not ask the projectproperties, but "1. screenshot of your project when the video is on the timeline" to see what you setted more wrong and unlogic.
Can you also give the MediaInfo of your used OBS files?
 

I did not ask the projectproperties, but "1. screenshot of your project when the video is on the timeline" to see what you setted more wrong and unlogic.
Can you also give the MediaInfo of your used OBS files?
 

Forgive me, I didn't understand what you meant.
here this is a screen of the video on the timeline


Media info Video on Timeline:
 

General
Complete name                            : D:\___\Videos\OBS\2020-01-02 18-44-12.mp4
Format                                   : MPEG-4
Format profile                           : Base Media
Codec ID                                 : isom (isom/iso2/avc1/mp41)
File size                                : 15.4 GiB
Duration                                 : 54 min 50 s
Overall bit rate mode                    : Variable
Overall bit rate                         : 40.2 Mb/s
Writing application                      : Lavf58.20.100

Video
ID                                       : 1
Format                                   : AVC
Format/Info                              : Advanced Video Codec
Format profile                           : High@L4.2
Format settings                          : CABAC / 2 Ref Frames
Format settings, CABAC                   : Yes
Format settings, Reference frames        : 2 frames
Codec ID                                 : avc1
Codec ID/Info                            : Advanced Video Coding
Duration                                 : 54 min 50 s
Bit rate mode                            : Variable
Bit rate                                 : 39.8 Mb/s
Maximum bit rate                         : 60.0 Mb/s
Width                                    : 1 920 pixels
Height                                   : 1 080 pixels
Display aspect ratio                     : 16:9
Frame rate mode                          : Constant
Frame rate                               : 60.000 FPS
Color space                              : YUV
Chroma subsampling                       : 4:2:0
Bit depth                                : 8 bits
Scan type                                : Progressive
Bits/(Pixel*Frame)                       : 0.320
Stream size                              : 15.3 GiB (99%)
Color range                              : Full
Color primaries                          : BT.709
Transfer characteristics                 : BT.709
Matrix coefficients                      : BT.709
Codec configuration box                  : avcC

Audio #1
ID                                       : 2
Format                                   : AAC LC
Format/Info                              : Advanced Audio Codec Low Complexity
Codec ID                                 : mp4a-40-2
Duration                                 : 54 min 50 s
Bit rate mode                            : Constant
Bit rate                                 : 192 kb/s
Channel(s)                               : 2 channels
Channel layout                           : L R
Sampling rate                            : 44.1 kHz
Frame rate                               : 43.066 FPS (1024 SPF)
Compression mode                         : Lossy
Stream size                              : 75.6 MiB (0%)
Title                                    : Track1
Default                                  : Yes
Alternate group                          : 1

Audio #2
ID                                       : 3
Format                                   : AAC LC
Format/Info                              : Advanced Audio Codec Low Complexity
Codec ID                                 : mp4a-40-2
Duration                                 : 54 min 50 s
Bit rate mode                            : Variable
Bit rate                                 : 183 kb/s
Maximum bit rate                         : 192 kb/s
Channel(s)                               : 2 channels
Channel layout                           : L R
Sampling rate                            : 44.1 kHz
Frame rate                               : 43.066 FPS (1024 SPF)
Compression mode                         : Lossy
Stream size                              : 71.8 MiB (0%)
Title                                    : Track2
Default                                  : No
Alternate group                          : 1

In that case it is the best to set your projectproperties this

and your rendersettings this

If you want to lower the bitrate, try it by only changing the average bitrate untill you see your problem again.

 

In that case it is the best to set your projectproperties this

and your rendersettings this

If you want to lower the bitrate, try it by only changing the average bitrate untill you see your problem again.

 

Excuse me, why is "full-resolution rendering quality" set to "good" and not "best"?
Anyway now I try with the settings you recommended and I tell you, in the meantime thanks =)

Excuse me, why is "full-resolution rendering quality" set to "good" and not "best"?

Look here

and read the manual, for sure for internet renders it is not needed.

So, I tried the settings of the project you recommended, then I did the rendering and I wanted to try:
-the first try with the settings you gave me

- The second test with these settings (I wanted to see if there was a noticeable difference)

As you can see, both videos are blurry and pixelated, even with the settings you gave me ... Now I don't understand if I am wrong or what, or there is something really wrong with the program or my pc ... (but I have also tried with adobe premiere, which I never use, and in any case the result was this)

No idea, I don't see this in my videos. Which build of V15 do you use? The latest is build 416.

No idea, I don't see this in my videos. Which build of V15 do you use? The latest is build 416.

Same, build 416

I have tried everything: update video drivers (Gtx 1060), try all the settings, but i don't understand why this is appening =/

What else can i do?

No idea, I don't see pixelation on my full laptopscreen(FHD), so no idea of what you are seeing. Maybe comes also because I'm not a gamer or gamevideo maker.
Maybe you have to use the same codec as the source video, in this case AVC and not HEVC