Even many of the more complex instructions often can translate into surprisingly short sequences - all sorts of loop structures have now various kinds of optimizations including instruction fusion that probably would not be necessary if we didn't stop using higher level LOOP constructs ;-)

But for example REP MOVS now is fused into equivalent of using SSE load-stores (16 bytes) or even AVX-512 load stores (64 bytes).

And of course equivalent of LEA by using ModRM/SIB prefixes is pretty much free with it being AFAIK handled as pipeline step

There's levels of microcode.

It's not too uncommon for each pipeline stage or so to have their own uop formats as each stage computes what it was designed to and culls what later stages don't need.

Because of this it's not that weird to see both a single rmw uops at, says the initial decode and microcode layer, that then gets cracked into the different uops for the different functional units later on.

Even RMW instructions are very RISC compared to what people used to mean by CISC.