DirtyDan
I also battery restricted the GrapheneOS launcher, which was routinely using a lot of battery for some reason. So far, no issues by doing that.
Don't recommend restricting the launcher. It's highly unlikely to improve anything for you. The reason it thinks the launcher uses a lot is because of how much of the UI it provides.
The last thing was location services. I don't know why, but GrapheneOS has been very battery inefficient when I have location turned on. I tried both the default rerouting that only uses GPS as well as Google location services with WiFi. The Google one was a bit better, but not by much. Google also requires Play Services to have location at all times, which then pinged my phone every 5-10 minutes, which I think played a role in the battery drain. Turning off location completely significantly helped. I'm hoping the new grapheneos wifi location services feature will offer a better alternative.
GNSS uses a ton of power. Our own implementation of network location is available in the latest release currently in the Alpha channel which should reach Beta soon and then Stable tomorrow. Enabling network location will save lots of power from many apps using it instead of GNSS. Best to use that, turn location rerouting back on (default) and turn off Location for Play services and the Google network location toggle.
Lastly, having more than 1 profile active at a time will also drain battery. Starting up profiles, including private space, also appears to use up some battery each time (1-2℅).
Starting them doesn't use nearly that much power. Keeping them running does use somewhat more power but it's mostly that you have more apps running. If you have 2 separate instances of sandboxed Google Play then you can expect more power consumption for it than the stock OS which uses a single Google Play across all profiles.