- I don't game that much anymore, but yeah, I hear games are still far from 100% on Linux.
- There are various graphical issues linked to fractional scaling (I think), such as random lines appearing near the edges of windows or windows leaving behind lines when being dragged around, etc.
- My external monitor doesn't appear to be affected by energy management settings (dimming/sleeping after some time, etc.) whatsoever.
- There is no option to disable the touchpad when a mouse is connected.
- Middle mouse button is paste instead of autoscroll with seemingly no global way to change it (I wonder who came up with THAT genius bit of UX).
- A lot of things can still only be achieved via the terminal.
Unix was the first to start using 3 button mice as standard, almost a decade before they really showed up in Windows world, and paste on middle mouse click has always been the standard behaviour in the Unix world, so changing it now would be very weird for *nix users. Whether Linux should follow the common Unix defaults or Windows defaults for their UI/UX has been a long running debate in the community.
I would personally be really confused and annoyed if I sat down at a Linux machine and middle click didn't paste, because that is the behaviour I've been seeing for literally 25 years.
Just don't force us to use the same behaviour by default.
Ctrl+C, Ctrl+V is superior. The shortcuts are easily accessible and you can use it to select and replace a specific part in the middle of text. If you try that with MMB-pasting, you will just overwrite your clipboard with the part of the text you want to replace, due to the selection-to-clipboard feature.
The answers from your "quick Google" only provided solutions for specific programs, solutions with self-admitted performance issues and a solution for X11 when I'm on Wayland. At a glance, the latter two look pretty hacky too.
Lastly, stop putting words in my mouth. I have said my issue was that the "Middle mouse button is paste instead of autoscroll with seemingly no global way to change it" and "I just wish there was an OPTION to change them". It is YOU who is forcing your defaults on me, without even a consideration that my preference may also be valid.