I suppose I'm posting this for my future self when I search for "Acer SB220Q remove stand" since it took me forever to figure this out.
Nothing was working to remove the original base. I didn't need to press/pry hard to get the stand to pop out. It should come out really easily with a light amount of pressure for anyone else that's struggling as much as I was.
NP! I think something is going on with lemmy.world. I had to log into one of my accounts in a different instance to reply to you.