TL;DR, you can try SRAM wide cranks if you need gravel sized chainrings. Funny BB systems but readily available everywhere. Can be used with normal chains.
Some BB386 cranks may work too
They don't sell Eagle cassettes smaller than 50. Or bigger XPLR than 44. You need AXS chain, cassette and derailleur, same for Eagle so it's not really possible to be swapping just cassettes
AXS stuff works great, gearing is good but I'd rather have the MTB derailleur with a big cassette to allow for a bigger chainring and still having a really low gear for loaded gravel climbs etc.
150ml or cl? You need a good amount for that tire