So I finally found a solution to my problem:
efifb
- Add
video=efifb:listto/etc/kernel/cmdline - Run
sudo reinstall-kernels - Reboot
- You will see something like this when booting
- Take note of the mode number matching your desired resolution
- Edit
/etc/kernel/cmdlineagain and replacevideo=efifb:listwith e.g.:video=efifb:mode=0 - Run
sudo reinstall-kernelsagain - Reboot
Now the resolution of my the boot output text is finally in 1440p:
Thanks for the help:
@BluishHumility @petsam @LamnaNasus @dalto
Finding this comment helped me.
EDIT: Well turns out that this here is a simpler solution for me: Stuck with bootresolution being too low - #11 by Melways
Setting the right value for console-mode in esp/loader/loader.conf… in my case systemd-boot was also using a very low resolution and although I used consolde-mode max in the past it did not have the desired effect. In my case the right setting is console-mode 0 and I found it by pressing r in the systemd-boot menu. This made me get rid of video=efifb:mode=0 again.

