prisi pixel 7a might have additional battery stress and battery life might be shorter
This isn't really the case. Many find that battery life is better when using GrapheneOS unless Sandboxed Google Play is installed and running in the background for push notifications to work. In that case, battery life should be close to the same as the Stock OS.
prisi i should use aurora store or run it through some containers?
Not sure what you mean here. All apps are sandboxed.
prisi anything else i should be aware of?
A lot of people think there's an issue with GrapheneOS and app compatibility, but that's not the case. In most cases where there's an "incompatibility," it's because an app relies on Google Play, which can be installed on GrapheneOS without granting special privileges to it.
Another cause for apps not working correctly is some app developers choose to make their apps not work on other OSes, like GrapheneOS, because they're not certified by Google. Google chooses to set things up this way, which is very anti-competitive. So to say that there's "lost functionality" is not really true at all. The functionality is all still very much there and if it weren't for this fact, virtually all apps would work on GrapheneOS without any issues at all.
But, yeah, some bank apps, some financial apps, and some games will refuse to work properly, but I'd say they're not the majority in my experience. You can check if your banks' apps are listed here on this list maintained by some community members: https://privsec.dev/posts/android/banking-applications-compatibility-with-grapheneos/