Just to close this off for now, I think maybe the most relevant factor to getting Abode and Eufy push notifications (I mean: immediate alarm beeping and screen notifications upon triggered alarms/cameras) to come thru correctly, after following all other established recommended directions, was in all the playing with settings and doing reinstalls, etc, it was when Google Play Services was installed (reinstalled) on phone before the 2 apps get installed/reinstalled. This importance of proper sequencing was mentioned in this thread by thmf and DeletedUser495 in late November. But it was soon after I did the proper sequence of uninstalls/reinstalls, giving permissions, signing into accounts, etc, that it worked and stayed workin.
Or Graphene dev's hacked my phone and fixed it.
Or it was fairy dust.
Thanks for everyones help.