Signal consumes half of my battery (no google services or microG)

• I have searched open and closed issues for duplicates
• I am submitting a bug report for existing functionality that does not work as intended
• I have read https://github.com/signalapp/Signal-Android/wiki/Submitting-useful-bug-reports
• This isn't a feature request or a discussion topic

Bug description

I installed Signal a few days ago, but it consumes close to 50% of my battery, more than all my other apps combined, when I barely even used it (answered one short call, sent and received < 5 messages).
I'm on grapheneOS so no google services and no microG. I posted the issue on reddit, and one person also on grapheneOS showed me a screenshot where Signal took 7% of their battery, with about the same time since full charge.
Battery optimization is off, I can't even turn it on. App runs constantly in foreground (which I assume is normal for the websockets).

Steps to reproduce

• use Signal with no google services or microG

Actual result: Signal takes between 40 and 50% of battery life
Expected result: Signal should take ~10% of battery life

Screenshots

Device info

Device: Google Pixel 3a
Android version: 10
Signal version: 4.62.4 (6520) from website

Link to debug log

https://debuglogs.org/ab69b49388ae783727c5d47318d25296311a9f8f0cce64991fb28ae0830f2a34

Start by reviewing the linked debug log and the reported setup: Pixel 3a, Android 10, Signal 4.62.4, with no Google services or microG. Reproduce the battery usage with minimal Signal activity and compare the result with the reported 40–50% consumption. Done means identifying and addressing the cause of the excessive drain, with battery usage returning near the expected level.