Can you give some examples of basic features that weren’t working with your dual monitor setup?

KDE might also help with this btw, as while I didn’t have any glaring issues with dual monitors in cinnamon (on Fedora), it improved overall when I switched to KDE. Used to have to change the audio output to my TV whenever I enabled it, now it happens automatically (plus the option to disable my HDMI audio if I preferred the “keep the same audio when switching to a different video output” behavior).

Only issue was that it didn’t work correctly the very first time, followed by it suddenly working the next time when I was intending to troubleshoot it.

Imo, KDE handles dual monitors better than windows even, especially if your secondary monitor is a TV you enable and disable depending on what you’re doing. Two clicks to toggle it, it handles different scaling seemlessly across the monitors (iirc, windows would “pop” to the scaling setting of whatever monitor they were mostly showing on as you moved them). Mouse cursor visibility improves when shaking the mouse, so it’s easy to find it on a giant screen.