Chromium low fps in potrait mode (left,right orientation)

[Ares-87]

I installed FullPageOs on my Raspberry PI 4 B (4gb), all working fine in normal mode, but when I rotate the screen in potrait mode (left,right orientation) by the variable inside "start_gui" script, Chromium goes laggy and with low FPS, I tried all arguments, but nothing.

With my arguments I have 36-57 fps, but really it's as if I had 15-30fps. The css animations are too laggy:

 --show-fps-counter
 --disable-gpu-driver-bug-workarounds
 --enable-features=VaapiVideoDecodeLinuxGL,UseChromeOSDirectVideoDecoder,CanvasOopRasterization,WebUIDarkMode
 --enable-gpu-rasterization
 --ignore-gpu-blocklist
 --kiosk

or

--show-fps-counter
--enable-gpu
--enable-features=VaapiVideoEncoder,VaapiVideoDecoder,UseOzonePlatform,CanvasOopRasterization,WebUIDarkMode
--enable-accelerated-2d-canvas
--enable-accelerated-video-decode
--enable-gpu-rasterization
--enable-oop-rasterization
--enable-zero-copy
--in-process-gpu
 --ignore-gpu-blocklist
 --ignore-gpu-blacklist
 --in-process-gpu
 --kiosk

If I leave the "normal" orientation, Chromium works great and smooth, with stable 55-58fps.

How can I fix the problem?

FullPageOS version: 0.14.0

[guysoft]

Sounds like a gpu issue when the screen is rotated.
There was an issue with that here that was closed:
#137

In general its not something that can be fixed on FullPageOS - if you install a plain desktop and run the xrandr commands here does it work?
https://github.com/guysoft/CustomPiOS/blob/devel/src/modules/gui/filesystem/opt/scripts/start_gui#L11