Gravel recommendations are hard as gravel can range from pretty-much-tarmac to CHUNK. But I'll try at least. For the record I'm riding a Canyon GRIZL, 2x10 gears and 45mm tyres. This I'm navigating on up to blue MTB trails so it is quite capable. If I would buy again I would get very similar specs except I would go for a metal frame, probably steel.

So recommendations then. I would go for a lot of gear range, on my I have about 430% and it is enough. Wouldn't mind an additional climbing gear or two. Not sure if a high end MTB 1x system can be gotten with drop bar shifters but barring that I would go for a 2x system. The extra range really helps. For tyres I would make sure the frame can accommodate 45mm as that will allow you to go CHUNKY if needed. But some 35mm fast rolling tyres would be a good starting point if you only have light gravel. Mechanical disc breaks would most likely be enough but if you go mid-tier it will most likely be hydraulic and those are great. Suspension I wouldn't bother with, go for more tyre instead. Oh and mounting points for EVERYTHING. Fenders, racks, bags, bottles etc. Fenders especially can be a godsend if you find yourself on slightly damp gravel, they also save the paint job. I would also try to find one with mounts for rear rack as I find a seat back sways too much. Personal preference there.