I think you got it the other way round - EU are upset that Microsoft used its massive customer base with Office to ship a video conferencing product like Teams for free in order to dominate that market.
I assure you, very few people would actively seek an individual Teams license. I’m very sure companies force their employees to use Teams as it’s part of the license.
Teams, especially when compared to Slack, is incredibly slow and bloated while being entirely lacklustre. Slack is lean and efficient at what it sets out to do (while being pretty expensive).