I just found this app mentioned on twitter. It's a version of Soundscape. I don't know much about it, but I installed it on TestFlight and from a quick play it looks pretty much the same. Lots of references to Soundscape even. I've not had a chance to go out wandering with it, but it looks very promising.
No Bose Frames support, sadly, but I guess that's not unexpected. But otherwise it's showing me places near by, allowing me to set beacons and so on.
It can be installed from here: https://testflight.apple.com/join/Y6Cj2cLk
I will confess that I know almost nothing about it but it's exciting to see something that feels like a credible alternative.
Has anyone else tried it?