Future of shinies in Tier 5 raids

So I can see at some point we will run out of shinies for tier 5 raids because many of the newer ones are still shiny locked. This year I am expecting we will get the remaining ultra beasts Stakataka and Blacephelon as shinies in raids since they were first released last year without the shiny. I don’t know how the other beast, Poipole/Naganadel will have its shiny released since it was only in research, not raids. Beyond that, there is still crowned forms of Zacian and Zamazenta, as well as Eternatus. They have not been released in Go yet but they have had their shinies previously released so they will come at some point, possibly later this year. I don’t know how they will go about doing Zygarde since it has never been a raid boss. Same with Solgaleo and Lunala, as they have never been raid bosses, they have had their shinies released in the main series, but their predecessors Cosmog and Cosmoem haven’t and we only got those by research. Beyond that, the remaining legendaries and mythicals from Gen 8 Galar, and the entirety of them from Gen 9 Paldea, which all have yet to debut in Go, have never had their shinies released anywhere. I wonder if some of them will slowly get released or if the game will shift to rereleasing older ones with backgrounds or new moves or something like that?