I'd like to mention that most IRL trots don't "hate" MLs - it's recognised that there are in general far more points of agreement than disagreement nowadays. This of course can greatly vary by specific Trotskyist and ML tendencies, but the major exceptions are very fringe.
xManager is a bit sus IMO because they claim their installer is open source while consisting of 15000 lines of unreadable machine-generated Java code: https://github.com/Team-xManager/xManager/blob/main/app/src/main/java/com/xc3fff0e/xmanager/MainActivity.java
They are also quite opposed to publishing the source code of the actual Spotify patches for rather vague reasons: https://github.com/Team-xManager/xManager/issues/324
Mind you, I still use it because it's pretty much the only option apart from YouTube front ends on mobile, but I would advise being very careful with the permissions you give it.
I use Graphene OS. While you can run it completely de-Googled, in order to run Play Store applications Graphene OS takes the route of sandboxing Google Play services. This means that they run with the privileges of a regular application and you can deny it access to e.g. sensors.
Sandboxed Google Play is practically identical in functionality to its non-sandboxed counterpart from the stock ROM, and nearly all applications should work. I can confirm that WhatsApp works for certain, as well as my banking app.
Calyx OS is another one that uses MicroG as a replacement for Google Play Services instead, but I have not used it.