I haven't followed new commits in the Nim repo lately, but I think I haven't seen any PRs that result in big changes to compile times except maybe <https://github.com/nim-lang/Nim/pull/19578> which might help you a lot if you have macros-heavy code.
- Did nimc become faster? Arrrrrx2
- Did nimc become faster? Hlaaftana
- Did nimc become faster? Yardanico
- Did nimc become faster? Arrrrrx2
- Did nimc become faster? PMunch
- Did nimc become faster? Arrrrrx2