When I have the time, I'll do a fresh install of Mint 20 on my main machine.I updated from 20 though.
Do it George, you know you want to.
I updated from 19.3 to 20 and pretty much broke my entire system.
HOWEVER, that was because this was originally a 17.3 system which I had upgraded multiple times and there was some crap hanging around that finally just broke. I had to reinstall.
Tony upgraded his system and had no issues at all. I think he started out on 19.1. He went to Windows 10 for a while because he really wanted to play games. Then Valve got Proton working with a couple of the games he wanted to play, so he came back to Linux because he discovered that he just really hated Windows 10.
I'd be curious to know what made it so difficult. I've had VLC installed on my system for a while, and it just went right in, and the necessary codecs were easy to find and install.
I'm sure there was something weird that I don't appreciate, because Kaitain is a sharp cookie.
With my Arch mentality regarding updates (must... always... update...) I tend to ensure my wife's Mint system is always updated, especially with new Mint versions. The upgrade from 20 to 20.1 went by without any issues at all. Then again, her current computer had a fresh install of Mint 20, the upgrade to 20.1 is probably not a huge change. Both Mint 20 and 20.1 are based on Ubuntu 20.04.
It should™ not be a problem to install VLC. It is in the official repositories and should be as simple as opening up the software manager and finding VLC and install it. Or just run the command "sudo apt-get install vlc".
Then again, there's always the chance of running into some edge case issue, but those should be rare. In any case, you are bound to find help here if you have issues.