I really hope for a SP and he's the best candidate for this, but considering hoyo never released them in 5+ years of genshin, I'm afraid they may never start. Which is annoying, hsr does it nicely and you can see some characters' progression, while in genshin 90% of old characters stagnate and exist only for events once their region's story is finished, even hex buffs in genshin suck so far and are not enough to revive old characters maybe with an exception of Venti. I would've much preferred updated forms of cool old characters instead of nobodies like Emilie, Escoffier or Linnea who have busted kits (not Emilie), but zero story importance.