That's a pretty reasonable approach. We publish multiarch base images for OCaml/opam regularly (e.g. see `latest` at https://hub.docker.com/r/ocaml/opam2/tags h

That's a pretty reasonable approach. We publish multiarch base images for OCaml/opam regularly (e.g. see `latest` at https://hub.docker.com/r/ocaml/opam2/tags https://hub.docker.com/r/ocaml/opam2/tags or https://hub.docker.com/r/ocurrent/opam/tags https://hub.docker.com/r/ocurrent/opam/tags for slimmer CI images).