Have someone call you on Signal. Missed calls galore. Also texts. It just dozez all the time (despite having been configured in Android to not let it sleep) and texts come late and calls get missed.
It doesn't "doze all the time" here, seems like you're blaming Signal when it's your phone's power management software not working as described.
The only people I know that have this kind of issue with Signal are all on Huawei phones, we've configured them and it's worked for a while but Huawei only seem to care about letting Facebook/Whatsapp/Teitter/etc.. run properly.
A bit of it. But it is besides the point: A messenger, that is working reliable and intentionally designed for the masses - does not come with the need, to fiddle with configs, to get basic functionality working.
I do not like Meta, but I never experienced with whatsapp, that someone send a message and this message just vanishes, so the sender thinks he is getting ignored. But exactly this happened way too often with signal.
But it's not fiddling with Signal configs, it's un-breaking the broken power management software phone manufacturers add on top of AOSP. This issue is not specific to Signal and if it were in their power to code around it, they would. Other apps get affected in the same way.
Whatsapp, being so popular, gets whitelisted. It has to work or people would be telling each other "don't buy Samsung!" (not unlike the situation with Huawai since the Play store got removed from their phones).
Messages getting lost entirely is a whole separate matter - so you got the two ticks telling you it'd been delivered, but nothing at the recipient's end? Was this a long time ago? I would stop using it too if I had that problem, I agree.
Like the other poster mentionied, you might have missed, that you missed things. It is sadly unreliable for me, too, which is just unacceptable with a messenger.