I have confirmed through personal testing that the bluetooth passthrough feature does work with this release. However, it requires the user to manually create a udev rule in the host machine as detailed in the dolphin documentation: https://wiki.dolphin-emu.org/index.php?title=USB_Passthrough#Linux
This is hardly ideal, but it's the way upstream recommends, and flatpak doesn't currently offer a means to improve it.
I've tested it superficially by playing wind waker.
There aren't any obvious regressions, the new feature to disable arbitrary
mipmap detection works as intended.
The Dolphin project is sadly one of those that never makes stable
releases and as such it is multiple years behind what the current
project actually is and users want.