Mensajes de texto duplicados

I have had this issue off and on for at least a couple years, received duplicate texts.  In the last few months it has gotten much worse, now sometimes up to 7 copies!  Doesn't seem to be related to wifi calling, doesn't matter where I am, don't have DIGITS, Hangouts is cleared and disabled, deleted whole threads, cleared Messaging's data and cache - all no affect.  The only things I haven't yet done this time around are completely wipe out ALL my text messages or a phone hard reset.  But I have done those in the past and it only helped partially and temporarily.  It doesn't happen with all texts, may not be all senders, and the only pattern I can see is that most, NOT ALL, the duplicated messages are short ones.

Another (separate?) issue for years has been sometimes, not very often, receiving messages MUCH later (hours to days to a couple times months) or not at all.  And some messages I send are never received.