Following the migration guides from SBS to Server 2019, I do not see a mention of removing the DNS zone for remote.domain.com. I would assume I am safe to remove that, but the guide doesn't say anything about it.
No, we do not endorse removing stuff we don't know if it can or will be used again. If you have no need for it remove it. There can be reasons to keep it. For example publishing an Exchange Server and because your users are used to using remote.domain.com you may want to keep it. Another reason could be is that you publish a RDS Gateway on that address.