Have there been audits if vaultearden code? Or comparison with bitwarden code? Otherwise I am curious on what do you base that code is as good as bitwarden?

Neither docker compose (unless docker compose build and you have source files) nor docker run will rebuild anything. OP has to check if he is using multi arch images and if not, has to change them. As for actual data in containers it varies app to app - I believe arm and x86 have different byte order, so for apps that are not storing data in platform agnostic format that might be a problem.