Hello @Dan.Wills, welcome back!
I am sorry to hear you are experiencing charging issues with your Sonos Roam 2.
As you can see from or Support Article Power adapter requirements for charging Sonos Roam, the charger you are currently using should suffice and you shouldn’t get the “Incompatible Power Supply. Roam 2 isn't charging properly” messaging.
Since you have other Sonos products under your Sonos System, it is safe to Factory Reset your Sonos Roam 2, without losing your current Sonos System and configuration, as a troubleshooting step and see if you get the error message.
If you are still experiencing this, I would suggest you to Submit Diagnostics while the Sonos Roam 2 is charging and then reach out to our Support team for live troubleshooting.
I hope this helps.