Clark I don't think anyone has empirical data on how much battery it drains but it does utilize more battery.
For anyone that isn't interested in turning on location services, a more manual approach I take is looking up the average sunset/sunrise time by my region and then adjusting whenever the seasons change.
Skyway Assume the same course of action for any of Google's services. Don't become overly reliant on a company that has shown they will do whatever they please in the name of data and money.
evol This is one of the sacrifices you're going to have to make in the name of freedom and utility unfortunately.
Apple for example, has unlimited resources to make UI stimulating enough to make people forget about their data privacy.
I can understand why the relatively small GOS Team doesn't want to take a second away from utility to focus on aesthetics, which can be very subjective.
Hatehavingtojoinanotherwebsite I'd recommend OSMand. It's the most feature rich open source solution you're going to get and pretty powerful once you get the hang of it.
You can make edits to your map if anything is missing.
This is probably going to be the best you can get.
Ammako No, not in this regard. You are still downloading data from an external source.
+1 on waistline. It's a well thought out app.
upstage4186 From my experience, non-foss apps tend to be very bloaty and unnecessarily large files. If you're using a VPN on top of that, this can further exacerbate slow downloads.
Ultimately, you should try configuring battery settings, data usage settings, doing automatic updates, trying the fastest server possible (if on a VPN), deleting unnecessary apps/tasks that are hogging resources, etc...
If still unsatisfied, I recommend trying to use the bank from the browser if possible.
Judging by the fact that it's a Pixel 5a it could be due to Zalgo/Special malicious text that overwhelmed it.
And then again, perhaps some advanced malware was abled remote code execution due to the Pixel 5a being more vulnerable.
Only you would be able to know definitively having all the context of the situation. Everything else is pretty much speculation on our end.
The best thing you can do is take pragmatic security measures moving forward.