There’s a lot in that article but thankfully they put a breakdown at the top saying disabling telemetry only disables what has usually been called telemetry, which is to say crash reports and analytics.
Not evidence of a backdoor.
The way to enable e2ee with no chance of unlocking on server side is to enable advanced data protection. It’s not on by default because people get locked out and need access to their stuff. The resolution that makes a cloud customer happy (they get access to the data again) isn’t possible with adp on.
Apple also famously fought the government in court to avoid giving up user data and the paradigm after that incident is the cat and mouse of intelligence agencies and cutouts like greykey and cellebrite. Ios almost always fares better than everything but graphene in those conditions.
Regardless things like periodic restarts and knowing the panic combination for rebooting into bfu are important.