I've tried on two different monitors, a 1080p Samsung and a 1080p Lenovo. Both had the issue with the display and both worked fine with the same cables when connecting to my PC laptop. The Mac Mini works fine on my 4K TV but I didn't intend on using it with it. This is a well documented issue in this forum alone along with the rest of the internet.
As far as mice, tried three wireless mice and two bluetooth mice and the same thing happens. I haven't tried a wired mouse yet since we don't have one, but also don't really want to because it's 2021 and wired mice are only for serious gamers at this point. This issue is also mentioned a few times in this forum.
Even something as simple as opening the Settings app takes several seconds after clicking when that is something instant even on a low-end PC. I did run a Geekbench test and it does match the expected results for the M1 Mini, so I'm not sure why it feels so slow and sluggish. Again, it's not a RAM issue as I have yet to do anything that would push the limits of the RAM.
I'm gonna try a re-install of the OS when I get the time (haven't yet) and if that doesn't fix it I'm returning it.