The M1 closely mirrored the A14 Bionic from the iPhone 12 (Pro), M2 the A15 Bionic from the iPhone 13 (Pro) and this the M3 “should” mirror the A16 Bionic from the iPhone 14 Pro / iPhone 15. If this continues we won’t have the new ray tracing GPU until M4.
Yes, but the A16 was a stopgap release, which only happened because Apple has to release a new iPhone CPU every year. The M-series does not update as frequently, and so it seems reasonable to imagine that the M3 is of the same "generation" as the A17.