I use signal as my main chat app. I think it sucks. I often don’t get notifications in a timely manner (very widespread glitch on android) and because it stores images inside its own encrypted box, the app size balloons incredibly quickly. I cannot just empty out photos automatically, as with whatsapp, i have to export them and then delete them - manually.
I think it’s still worth it to not have facebook all up in my business, but the end user experience is shit.
Re: the notifications not coming, I’ve seen it similar from WhatsApp too. I reckon it depends much on which app you use more, so it gives enough battery time to keep aware of messages. Now I use Signal more, I think I’ve had more misses on WhatsApp.
That said, I’ve had a few weirder misses (for calls only, I think) that don’t seem to be from battery optimisation.
Settings > data and storage > manage storage > review storage > select the media you want to keep > save
Your snark is misplaced. My complaint was never a complete lack of functionality, it was that it is not automatable, it has to be done manually, as the commenter above you so tersely but pointlessly, explained step by step.