Skills course (or maybe decent skills book (or video?) and put some time into getting what they’re on about, try putting stuff into practice and going back to said resource)
Also try building up your fitness?
“find it sometimes hard to stick with my riding partners, one of which has a stumpjumper FSR and the other has a full sus santa cruz”
“am hovering around either a orange alpine 160, but i think its too much bike for what i ride, and a orange five AM”
If you decide you want to go down the full suss route, you ought to try a few first and then don’t ‘over-suss’ yourself (too much). You say you want to keep up with your mates, a ‘bigger’/burlier bike isn’t going to help you go quicker on stuff thats up or anything too pedally?
I’d have thought the obvious would be to go something similar to a stumpjumper or santa cruz (which one is it?). So 140/150mm?
Given the build of your crush, could you hunt down a not ridiculously pricey full suss frame to go with that build, 140mm taper forks? (maybe even ebay something?)