I have an old (but rooted) phone running Android 5.1.1 (Lollipop).
I realized it runs many background processes which I absolutely don't need.
I can stop them manually via
Settings > Apps > Background processes, however I wish to keep them disabled: they slow down the cold-start of the phone which I don't like.
So I'm looking for a way to not just disable but completely ban certain processes (i.e. ban them from starting).
How can I do this on these old versions of Android? Unfortunately Google is quite blurry and noisy for these search terms.