Want to try a new distributor ? Nothing to setup, you just need to open the app and grant the requested permissions. It follows the last version of the UnifiedPush specifications: Sunup !
Most of the applications supporting UnifiedPush should work without any issue. But a few may break, so if one doesn't work, let us know: the application may not be following the last specifications.
Regarding Matrix, a workaround has been implemented until webpush is supported by their specifications. Element-X has a patch going on to fix the default gateway (but Schildinext works), all other clients already supporting UnifiedPush should work