@ljutica
It's a bit a workaround to get notifications on signal, but it goes like this:

Get UT Tweak Tool: https://open-store.io/app/ut-tweak-tool.sverzegnassi Open UT Tweak Tool -> Input Password -> press the menu -> app scopes -> Signal -> Turn on "Prevent app suspension" Open Signal, in each conversation for which you want notifications you open the conversation -> menu - > turn on notifications leave the signal app open and running the background and you should receive notifications when messages come in.

It's definitely got some quirks...