We spent significant time over the last couple of years on chat notification reliability Alex.
When did you abandon Chat? @jordan-violet are you still experiencing the issue in the OP?
Thanks for your efforts Sam. For me personally the notifications worked most of the time, but would randomly drop out and require refreshing the Discourse page to get them working again - but historically have not worked at all, or worked sporadically, and definitely have a habit of being turned off completely at discourse upgrade.
We stopped using chat this week after adopting it at the start of 2023. Notifications in Google Chat just worked for the whole team including those who we’ve had regular issues with or never managed to make them work.