My Pixel 4a stopped charging and then died today. Asurion said the battery and charging ports were fine and at the correct voltages, so thus the motherboard was likely the issue. I have a very recent Seedvault backup which I imagined included my Signal messages, but after restoring the backup to a new Pixel (6a), my Signal messages have not been restored. I also "had" a very recent backup by Signal itself of my messages (~ 1.5 GB), but that file is, unfortunately, on the dead phone.
Assuming the motherboard is the problem, what options do I have for recovering my Signal backup (e.g. by first transferring it to my computer)? If I can find a repair shop which doesn't require a factory reset prior to repairs, can any board repair in fact be done without invalidating the encryption? Are motherboard issues typically overdiagnosed, and/or are battery/charger issues typically underdiagnosed?
I'll look into manually decrypting my Seedvault backup to verify that no Signal data is there.