Without seeing your MediaInfo Properties (required for support here), I can tell that your video was almost certainly shot in HDR10 (ST2084 PQ) format, and has not been correctly recognized and dealt with in your Vegas Media, Project, and Render Properties.

You have a number of options:

1. Don't shoot HDR10 if you intend to deliver 8 bit 709 4:2:0, the most universal output format in use worldwide.
2. Learn to set your Vegas Media, Project, and Render Properties correctly. There is a learning curve that as a new user, you may not wish to tackle at this time.
3. Transcode the footage to 709 Limited in Shutter Encoder. You will absolutely want to do this if your video is also Variable Frame Rate.
4. Use the free LUT Transform I designed especially for this purpose in Vegas. https://drive.google.com/file/d/19Hx_Kv6ThYYEBSjOfWO-M-0JvfVPxa-0/view?usp=sharing

Thank you very much for your quick answers. How can I get Mediainfo?

Mark-y: How can I use Lut Transform? I have downloaded it but I don't know what to do. I think this tool can help. Can you help me, please?

Thank you very much for your quick answers. How can I get Mediainfo?

@Sergio-HerreraFuentes Hi,

The App is called MediaInfo, download it, it's free & a fast download with no added adverts or any of that rubbish. https://mediaarea.net/en/MediaInfo.
After downloading, right click on the media file in your Windows folder, open MediaInfo, choose Text from the options at the top, screen capture that page or Copy & paste the information in a new comment on here using the arrow button next to the smiley at the top of a new comment 👍

Like this -

I have found the Media Info app. I think this is the information that you need:

Hello, again: I think I have found a solution. I have changed the project properties. I have disconnected HD10 and I have changed it to HLG. After that, the image is more natural, it seems like the original video. Thanks for the help.

Mark-y: How can I use Lut Transform? I have downloaded it but I don't know what to do. I think this tool can help. Can you help me, please?

Go into the project media window, right-click on the media, go to media Fx, add the LUT Fx filter and then select the LUT to convert it.

If you don't have an HDR monitor (1000 nits brightness) to view your footage on it would look wrong so I'd just shoot non-HDR and work normally in a standard dynamic range space.

Hello, RogerS: Thank you very much. I will try it.

@Sergio-HerreraFuentes I have an s23 Ultra which should be similar. The Advanced Video Options that work best for me editing in Vegas on my regular 4k monitor are: HEVC & Zoom-in Mic both checked; High Bit-Rate, HDR10+, and 360 audio all unchecked. If I choose H.264 instead of HEVC, then High Bit-Rate and HDR10+ become unavailable... you might want to try that if your computer has difficulty editing HEVC.

You use the LUT transform in the Vegas LUT Filter Effect.

Please read the Vegas Help first before posting, thank you. I am a volunteer here; I don't work on demand.

https://www.vegascreativesoftware.info/us/forum/got-questions-consult-the-tutorials-first-please--120282/

@Sergio-HerreraFuentes Here's the approach I'd take if I made the same mistake with the phone settings. I took your 2 image shots and threw them into Vegas side by side and looked at them together with the scope in the Color Grading Panel. I have the scope set to a scale of 0 to 100 by unchecking Studio RGB.

In the shot above I disabled the CGP FX so you can see the scope without the adjustments. Enabling CGP you can see how the level and saturation adjustments indicated cause both halves of the scope and the 2 images to look more alike.

I arrived at the settings by 1st looking at the Lift setting but the bottoms of the scope already seemed similar so I left it alone. Then I raised the Gain setting to get the tops similar. Lastly I moved the Gamma level to get mid-range into similarity. The red barrier strap looked rather weak so I also raised the saturation to make it look like the other shot... personally I think it's a little high.