Box64, FEX-Emu and other x86-64 on ARMv8 emulation projects cover that gap and explicitly target gaming as a core use case. And of course there's Apple's Rosetta, which we know is good enough for gaming on ARM macOS. Apple has released a Linux version which should technically be able to run on Asahi, but I'm unsure of the legal situation around this.

You can always do this: https://wiki.debian.org/QemuUserEmulation to run amd64 binaries on an arm64 machine, or vice-versa. Docker desktop sets this up so you can pull amd64-only Docker containers on your M1 and not notice. I did some very minimal testing and it's not even insanely slow or anything (but obviously for many games, you can't leave this much performance on the table).

I do this on my workstation and can run anything, it's quite nice:

  $ lscpu | grep Architecture
  Architecture:                    x86_64
  $ GOARCH=arm64 go build main.go
  $ file ./main
  ./main: ELF 64-bit LSB executable, ARM aarch64, version 1 (SYSV), statically linked, ...
  $ ./main
  Hello, world.

Do Rosetta apps utilize the GPU on M1 (on macOS)?

Yes. The calls to the platform graphics APIs and underlying drivers are identical (and literally hit the same code), whether from x86/Rosetta or native/ARM64.