As I would guess most of the people here are using displays from waveshare.com (not endorsing).
I know connected display is experimental feature and not supported ... anyway ...
... if anyone wants to rotate image you can do the following (edit existing file) ... (everything is slower, but anyway)
and add this (this is checked for RPI4).
you would also need to do some work in /boot/config.txt as required by waveshare wiki
as far as touchscreen is concerned it is required to install libinput (xserver-xorg-input-libinput) in order to do anything... since apt-get does not work with buildroot what are my (our) options for installation?
Since topic is unsupported can someone post what touchscreen models they used and their experience