My company is a service provider who depends on this 3rd party product, which happens to be the industry leader for the segment they are in. It doesn't matter how good my company is, we're beholden to others. My company actually just spent about 320 man-hours making an "emergecy fix" that we can use if necessary. It's a janky as anything webview, but it gets the job done.
I'm not faulting Apple here, just stating that it's not always easy to be on the continuous upgrade carousel. Especially when you're trying to juggle the upgrades with application updates and managing unplanned covid related releases at the same time.