Hello, i have a problem:

i am using Vegas Pro 15.0, and i have never edited or exported anything in 4K, i am doing a roadtrip soon and planing on filming it and editing it, i did some tests with my iPhone X and a Gimbal, everything inside Vegas works fine untill i want to Export the Video, my goto codec MAGIX AVC/AAC MP4 wont let me export 4K with more than 12fps, it always resets the framerate to 12fps ( Half-Film) for whatever reason, how can i fix this issue, do you need more information? is there any other codec i should use, preferably something with lossless quality, i dont mind big files and long upload times but the videos get compressed way too much even tho the bitrate is on 50mbps