Teams doesn't have to be good to succeed. It just has to exist. It's not even very important how good it is. Given it exists, IT will make everyone use it on Microsoft's behalf regardless of how bad it is. Or another way to look at it is that the real customers for Teams are IT departments. It makes their lives easier because they don't have to do anything and it meets all the compliance requirements they are suppose…
Someone should make job board where people can filter out companies that use Teams instead of Slack or Discord.
Teams is chosen in companies where the organization is so big that "unification" is seen as a big plus.
What you're out after, are smaller organizations where choices are made based on what people working with those things actually want to use.
So look for headcount rather than what chat program they use, because the headcount will affect more choices than just what chat program you'll end up having to use.