I tried to apply Markdown Syntax in my Teams Forum but actual published page is not the same as was previewed.
For example the H1 H2 H3 heading elements, it is working in the preview but on actual it doesn't.
See actual forum page sample:
https://lichess.org/forum/team-knight-movers/everyday-habits-practice-coordinates#1
I imagine they concluded that letting users make an <h1> poses an existential threat to the charity.