Can't you still work around DASH by changing your user agent, claiming that you are running Safari? (It used to be the case, but I haven't been in the streaming industry for years now so it may be obsolete)
I mean “work around the fact it doesn't work with DASH”
Also, MPEG-DASH is the typical bloated design-by-committee standard, that have twenty ways to do the same thing and that makes it very hard to implement fully. It's PDF or SVG all over again.
(I uses to work on an implementation of a DASH web player that had much better coverage of the standard that the reference implementation back in 2015, and I can tell you it was a PITA)
HLS, while a bit primitive in a few annoying way (inclusing the fact that it mandated, at the time, the use of MPEG-2 TS), is at least a pragmatic standard that is reasonably implementable. (Even though HLS.js being really good compared to the DASH alternative makes it less likely that you'd need to do it by yourself).