Is this from experience or because Apple said so?
As someone who has years of experience in sideloading and never had any issues. I will say, the
potential is there. Just like the potential for scam app to appear in the Appstore. The actual risk is entirely up the user. For some sideloading actually improved security and privacy. In my case it required rooting since non-root firewall stills shunt your data through a 3rd party server. Meh. Root firewall blocks data directly from your phone.
If iOS (and Android) has a built in firewall, I would have no reason to want to sideload.
Sideloading would be block by default. It is on Android. The user has to unlock by choice. For iOS, it should be a lot more than just toggling a switch. Bury under a ton of security so the users can't say they turn it on by mistake. "
I pushed UUDDLRLRBA 2x by mistake."