Android ... improving privacy
Hate to break it to you, but google doesn't allow any privacy on their ad-serving os.
I would agree that some version jumps do offer material improvements in feature sets, but they also come with further erosion of your privacy.
I'm not sure, but even if that's true, there are other stores available on slightly older versions (fdroid, obtainium, aurora). Note, however, that some newer versions of android will prevent app installation outside of their official play store (they tag it as "side loading, but it's actually just installation).
Edit. Spelling.