never paid much attention to bike geometry and stuff like that, but has this anything to do with the fact i cant wheelie for shit on my fancy 27.5 160 enduro bike, yet im like wyn masters on my old 26″ 140 orange five?

Nah, not IMO. It’s all about finding the balance sweet spot.

Longer chainstays on the 27.5″ bike, plus the front half’s probably heavier…

Is your position actually the same on both?

When I changed my Fox 140’s to a Pike 150 on the Five it felt a lot heavier at the front end, probably due to a slightly bigger station and 10mm increase.

This made wheelies a lot different to what I was used to but you just alter your weight / balance point slightly to get the correct feeling once again.