You will not have access to DEVONthink from two different Macs. You will have access to a local DEVONthink database on each Mac.
This goes for DEVONthink To Go 2. You will not be accessing DEVONthink anywhere but on the local device.
Check out the built-in Help on Syncing. If you’re so inclined, you can use Dropbox as a Sync location (which is NOT the same as a database location).
PS: It’s not just frowned upon, it’s not data-safe, even if you seemed to get aay with it for some time. (I smoked for 25+ years and am LUCKY enough to not have lung cancer, but I would never say it was a healthy thing to do! )