Wrong display resolution, cant change



I have a RPI3B+. i have an old vga monitor (1280x1024) connected through a not cheap hdmi->vga adapter. Using the lxqt flavour.
On other raspbian it does not recognize it automatically either, but i can change it with raspi-config.
On arch-linux-arm, it does it automatically (but i think that is because i first boot in cli, and then install the graphics.
Found THIS on the arch wiki than i found out rpi doesnt use grub. (yeah i just bought a pi, im quite a noob on arm)
Tried to force 1280x1024 with a xrandr command, negative, said sth not found.
Can i maybe force it through lxqt? where are its display config stored? any ideas?


The rasbperry pi uses settings in a config file to determine the resolutions.
So check in either /boot/boot.ini, /boot/boot.txt or /boot/config.txt.