Shimano Direct Mount Chainrings

Are they compatible across the entire range, i.e Deore and upwards?

I have some Deore M6100 cranks which will need a ring soonish and looking on ebay they all say compatible with m7100/8100/9100, but no mention of m6100.

The fitting looks the same, but am I missing something?

Yes – they are compatible AFAIK.

(I run Deore and XT cranks across various bikes and use the same direct-mount chainrings on each. 32t for my son and 28t for me).

XTR may be different.

I have a Deore ring on an SLX crank, Shimano says it shouldn’t be compatible but it fitted just fine.