I would have a few other ideas. The cursor working but can't click on anything usually means you are not running default resolution because somehow scaling or maybe swapping between different monitors or something similar I think can cause rF2 to go wacky.
IE: Where you have to click slightly left of all buttons for them to work.
Also seen this in other gmotor sims.
Actually it just happened to me swapping monitors when I clicked on single player it started online instead. Move the mouse to the left of single player highlights it and works and all other tabs from then on are offset as you will.
When you select correct resolution and refresh rate in graphics the buttons will work properly.
I use GME config mods to fix this in 2 clicks
Very handy for anyone uses multiple resolutions.
So reinstalling rF2 simply resets config.ini, when it first boots it will set your default monitor resolution and rF2 UI would work normally. Most likely all you needed to do was delete the.ini
and restart it.
edit:
Also with some HD TV can cause effect when they reset to 30Hz from 60Hz.
My 2024 Neo QLED does same thing when I jumping monitors and dragging windows
it can reset from 144Hz to 60Hz.
I will notice this straight away because something is acting clunky or not right.
Since I matched refresh rates with the 2 monitors been much better experience.
Samsung Neo GLED 4K@144 Ultra Gear GSync 3440@144.