I have an old fire tv and never tried to stop automatic updates on it, it has become so slow and unresponsive that I'm barely able to switch inputs to use something else. Netflix is the only app that still works on that tv.
Often it’s CA certificates expiring. My old Toshiba had app rot set in like that, where after about 5 years none of the built in apps worked any more and the errors appeared to be TLS related. I suspect that was due to pinned certs to prevent MITM pirating.