The monotonicity alone makes the required state _very_ easy. Adding (timestamp, jwt_id) pairs to a monotonic set which you occasionally switch over to a second, fresh set (checking against both, adding to one) requires zero coordination in the critical path. The only coordination required is about when the sets are switched, where you need to ensure that you leave ample time for old JWTs to expire before clearing the corresponding revocation set entries.

Rather than blacklist JTIs would it not be simpler to keep a valid after date on the user? Any token issued before that date is not acceptable

Then you can't have users sign out of device A while remaining signed into device B.