Thanks for the reply.
XC- Bike? Yes, but no (more) racing planned.
5'9": No, (sorry for the mishap)I am a rather short legged 1,70m or if I do it right a bit less then 5'8.
As said, my Enduro Bike is a Canyon Spectral 27,5 16" Frame and feels just right.
For less demanding /flat Terrain I have a 29 Canyon Nerve (100mm fullsus) in size M. This is the one I do not feel comfortable with. Great bike but it just does not feel right for me. Even on flat single track I seem to have troubles to keep the bike on speed in thight sections. Doesit have to dowith the size,the wheelsize or just the weight of the bike? I felt even more confy on my 26 RM Vertex,but agree that a bigger wheelsize brings Advantage,but if Ineeda29er is still anopenquestion. Guess I just need to testride both Options to find the answer