Keep in mind that many (all?) smartphones are deliberately obsoleted within 2-3 years of release - as an example, my S5 (released 2014) only supports through Marshmallow (obsolete as of 2016). Any apps requiring Nougat or later are unavailable to me. Given that I personally use my phone for communication, browsing the web, reading, and note-taking (and occasionally SSH), this isn't a concern, but it might well be a deal-breaker for a Bose soundsystem, unless their apps happen to be backwards-compatible (though being IoT-connected would be enough to make me avoid it like the plague regardless).

Same situation here, but with an S6. I would probably pay a subscription for an AOSP based install that was supported and got updates. The volunteer level of support for supporting different devices that LineageOS gets means that for some phones (namely the one I'm using), have poor or nonexistent current offerings. :/

I reccomend installing lineageos. It works great on the s5 and still gets regular updates.

Its not too hard but you may want to dedicate an hour on the weekend to set it up.

I run Linux on my computers and degoogled android on my phone. Do I not deserve to have speakers because I don't run google spyware? Why should speakers even need an app, I just want to plug them in and have sound.

Yea, But a soundsystem is supposed to last much longer than an app.

It might work now, what if someone needs to reconnect it 3-4 years from now and the app no longer runs?