Hello99,
you posted right after Shabbos in the US. Are you here now, or are you still there in EY? Did you decide not to post while it’s Shabbos in the US, or “poonkt” that’s when you posted?
I looked up the Yabia Omer. His reason to be meikil meikar hadin (he still holds it’s better to be machmir) is that the Riva”sh is a “tana ham’sayeia”. I think, though, that the Riva”sh is arguing on the Teshuvas HaRashb”a (brought in B”Y 119) because the reasoning of the Riva”sh should nor asser the yayin of a mechallel Shabbos, since he doesn’t ever make yayin nesech.