No, backstab to have advantage is not a thing in DnD. Highround to have an advantage and give disadvantage is not a thing. Shoving is not something you're trying at every turn, it's... A tactical choice.
Dunno mate, friend plays D&D every week and has mentioned things working that way in 5e, so I'm more inclined to believe them than someone who clearly has issues with the game on a forum.
Yeah, or you could read the rules to make your own opinion. It's not how it works in DnD.
I'm not playing the TT but I'll be glad to teach the rules to your friends
