Hi Luke,
Since minor versions of the PB IDE cannot co-exist, if you want a fallback I would suggest to install PB 2019 R3 to a different physical or virtual machine.
As far as deploying your apps, I suggest trying out the new PowerClient feature (added to PB 2019 R3) as it takes care of deploying the runtime to your users as well as the app itself and automatically updates this whenever there is changes. https://www.appeon.com/products/power-client
The version indicator is no longer on the file names, but now they are in their own folders that are versioned. And starting from PB 2019 R3, you can have multiple versions of runtime installed on same machine (even if they are minor versions). Before you could not do that.
Please carefully read the documentation about the changes we made to the runtime: https://docs.appeon.com/pb2019r3/whats_new/Separating_Runtime_from_IDE.html
Best regards,
Armeen