I use ARM containers locally to dev and test locally, check in the code and the build server creates an x86 image for deployment to the server.
Worst case you have to build the ARM container yourself locally and tag it with the "remote" name and docker will just use it instead of pulling the remote version.
you have to add support for your infrastructure to support building of everything for two architectures. sometimes problems are architecture dependent. if you have to use x86 containers for some reason, they will be dog slow because you'll be running the kernel under emulation and in userland rosetta won't help.
Not dog slow but slower than they could. My experience is: a Rails test suite takes 75 seconds on my 2014 Intel ZBook laptop with a SATA bus and a SSD. It takes 50 seconds on a M1 MacBook. I'm sure I could have found some expensive Intel laptop as fast as that back in 2014. Docker on the M1 runs with something called Mutagen and we have two different docker-compose.yml, but one Dockerfile.
Rosetta absolutely does help.
You register rosetta (which can be mounted into the VM using macOS's virtualization framework) with binfmt_misc and your x86 binaries inside the VM will run through Rosetta.
I use ARM containers locally to dev and test locally, check in the code and the build server creates an x86 image for deployment to the server.
Worst case you have to build the ARM container yourself locally and tag it with the "remote" name and docker will just use it instead of pulling the remote version.