After 4a and 6a, now is the time for 7a to shine!
Though, is it still in early beta and apparently very few models seem to be affected and there isn’t any word of system update to nuke the battery life on this model. But it goes to show that Google is treating the A series really badly.
Replying to your edit; I use a custom ROM (CalyxOS) and am unsure if I have received any sort of update battery wise. My battery feels the same so far. I will be taking full advantage of Google’s free battery replacement program.