Looks like you’d need to buy some sort of pedals with the Commencal, unless I’m reading it wrong. SPDs are great once you get used to them but it’d also mean a shoe purchase of course.
Anyway, looks fine as an entry level bike to my eye, and that part of the European market is full of decent entry level suppliers (they’re competing with Decathlon after all).
On the growing thing, I definitely started most of these things late. I’m barely even shaving at 36. If i’d stopped maybe two inches shorter I’d probably have been fine with the biggest off-the-peg bikes (and good old Surly make bikes big enough for me, so I’ve got a karate monkey). I reckon you’ll probably be fine with most XL MTBs, but like I say, I wouldn’t compromise down a size. The bike that knacked my knee was my absolutely adored Airborne steel Black Widow, a 21″ frame. Cyclefit in London then told me to stop being stupid, I had the longest inside leg they’d ever measured, for gawd’s sakes go custom.