No? Performance is implementation specific, they’re usually cheaper than ARM since there’s no core ISA license overhead, and while the core instruction set being extremely limited does cause a little bit of tension in compiler land, most cores with a baseline set of extensions get reasonable code generation these days.

One of the main reasons RISC-V is gaining popularity is that companies can implement their own cores (or buy cheaper IP cores than from ARM) and take advantage of existing optimizing compilers. Espressif are actually a perfect example; the core they used before (Xtensa) was esoteric and poorly supported and switching to RISC-V gives them better toolchain support right out of the gate.