Do your tags transmit (or can they be configured to transmit) any stable identifier like an iBeacon packet, apart from their function as Google FMDN devices? If so, local tracking should be possible using Bermuda etc, and a local integration to ping them to chime might be also.
But it’s quite possible they act only as FMDN devices, in which case I think you’ll need to have a FMDN integration. But once someone cracks that (and it looks like it should be do-able) that should also allow us to derive/verify the current BLE MAC so that Bermuda etc can track it locally as well.
Currently this is possible with OpenHaystack AirTags (statically-keyed open-source AirTag clones that can be queried over the Apple FindMy API. GitHub - malmeloo/hass-FindMy: Custom Home Assistant integration for Apple's FindMy network. (it’s a little off-topic here but it’s sort of where things are at in the broader sense, imo).
Some good related discussion here also: Implement Google Find My · Issue #51 · biemster/FindMy · GitHub
@awh 's link to leonboe1’s repo seems to be the “head” of current actual efforts that I’m aware of. Google requires that manufacturers and I think end-user accounts register their devices so things are a bit trickier than the Apple system, but at least it’s openly documented - I’d think that for someone with the time and motivation, it might be possible to implement the registration and tracking of GFMDN tags entirely within HA - at least as a “development device” which would require frequent re-registration, but it will be a decent chunk of work (and I could easily be missing something that would be a total roadblock).