Is there really much difference between Deore and XTR
Yep, Deore is pretty nasty- they can die very fast in wet conditions or hard use (I killed one in 6 hours, the races dented! To be fair, in use it was not meant for but still, a good test)
XT and XTR seem functionally identical to me, they’re different inside but I don’t think it adds up to any real world benefit.
Gusset EXT24 as above is a really good option- comes in different colours, decent life from new but more importantly takes standard, common bearings unlike Hope so future servicing is dirt cheap. Just don’t break the tophats too badly, and don’t get the ceramic one, not worth it.
Hope has one real advantage, their BB is very resistant to overtightening, whereas a lot of BBs are very sensitive to it, and a lot of people overtighten cranks