If you're sandboxing Google play services, you are, by definition, still installing play services. They are still running, but are sandboxed. So I don't see how you see any less battery drain.
I run MicroG instead of the proprietary Google play services, and while I do see a bit ofl an increase in battery life for light usage, for medium and heavy usage it's pretty much the same. Admittedly my battery is pretty old.
With the amount of Linux nerds on Lemmy, I'm shocked there's an a TUI client for it.
Maybe I'll have to make one someday.