When I open an image in full screen, the image flashes in different colors, that's when I have the largest open. If I click F once, it works fine, but if I click F again, it starts flashing.
Have the latest update of PS.
Try unticking "Use Graphics Processor" found under the Performance tab in Photoshop preferences, then closing and reopening the application.
It helped but won't I loose other things when its off?
Check out »Which features leverage the graphics processor?« on this page (the list doesnt’t seem to be complete, though, the Rotate View Tool is is missing for example):
Turning off the GPU Processor probably won't affect your "other things", but you may need to turn it on for something like using the Neural Filters.
I reported a bug in Photoshop version 23.5 which hasn't been fixed in version 23.5.1 and it could be related to the issue your seeing.
I have an Nvidia RTX 3090 and there are ongoing issues with Nvidia GPU drivers and Photoshop version 23.5.x
OK, just wondering because my computer is new and the graphics card I have is NVIDIA GeForce GTX 1650 and it works fine except in largest display