how to not stretch the 4:3 (1024x768) resolution on a wide monitor (1920x1080)?

I need this because my dell notebook video card is only not freezing if I use nomodeset on grub. But then, I am limited to 4:3 resolutions (right?). So, I am looking for a way to not stretch the screen image (1024x768) on the full resolution (1920x1080) monitor. I wanted to let the 1024x768 (or 1440x1080) be in the middle of the screen (with a black margin on each side), not stretching! I cant find a way to command xrandr to do that, I tried many things on the --output and --pos but nothing help to accomplish that. Even better would be if there was some way to tell VESA to use 1920x1080 directly tho. related: https://unix.stackexchange.com/questions/644634/normal-hd-on-ultra-wide-monitor-without-stretching-pixels wont work: https://askubuntu.com/a/614242/46437 https://superuser.com/a/1245757/157532 (for 2 monitors, not my case) https://superuser.com/a/485165/157532 :( ...