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.
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.