It's really hard to keep up with Apple's support for open codecs: it's always bad, and it always improves one minor step per year at best. Evidently, I'm behind on it, because I've mostly given up on trying to make software I work on work well with Apple devices by this point. (I can't tell you exactly what's wrong, but I've noticed I still can't get most WebMs to load in Safari on my M1-based iPad... some of them do, some of them do not.)

Apple is hopefully noticing that while major publishers can be swayed by this sort of behavior, lack of support for open codecs and open formats is going to make the iPhone and iPad web experience much worse for people who veer outside of the mainstream for a bit.