2019 is _ancient_ in terms of web browsers... What you call churn is actually mostly moving the web platform forward and fixing exploits. There's no way for the modern web to work without the rapidity of development browsers are undergoing.
Pretty sure that's the OS we're talking about, macOS Catalina 10.15? I am running it right now, and not pining for the new shininess of the more recent OS releases. If it wasn't still getting security updates, sure (but I've got a few more months, at least).
