Note that ACME profiles are new, to the extent that the draft spec is (a) personal (and not prefixed with draft-ietf…), and (b) currently versioned -00:
Yeah... thankfully, it's "pretty simple" for clients to implement. Just add a JSON field to your payload and that's it. (There's a little bit of error checking logic and input validation, like making sure the value is valid, but overall it's not too complex, unlike ARI, which is much more work.)
* https://datatracker.ietf.org/doc/draft-aaron-acme-profiles/
The ACME spec is:
* https://datatracker.ietf.org/doc/html/rfc8555