Migrating RTC to non AD environment?

We have a very old installation of RTC (3.0.1.4) which we are trying to migrate. The system is hardly used anymore but we still need it for the odd bit of leagcy info that we need out of it occasionally.

We want to move it out of its current on prem solution and put the application server up into the cloud. I think I'm okay with the moving of the server and we can fudge the connection names using a hosts file to get the app talking to the db.

But we currrently use a legacy Active Directory domain for authentication, and we don't want to move this and it wont be connected to the new environment). Is there a way that I can change the authentication to a simpler system than AD? Ideally as its only a handful of users who will log in once moved can it be as simple as local server authentication or similar?