Is it possible to allow sideloading and keep users safe?

"sideloading" connotates something that is negative.

On systems before apple's locked-down iphone, it was just called "installing".

The PC revolution started with people just inserting their software into the comptuer and running it. You didn't have to ask the computer manufacturer or the OS vendor permission to do it.

And note that apple doesn't allow you to protect yourself. You cannot install a firewall and block arbitrary software on your phone. For example, you can not block apple telemetry.

Which is why alongside freedom came the business of anti-virus.

Never in 20 years of using Linux/Macs I’ve ever needed anti-virus.

Never in those 20 years did I need one on Windows either. It turns out if you vet the software you install in the first place, malware is pretty rare. That isn't the bar for most regular users of software though.

Working in retail tech support, we got folks bringing in their new macbooks, freshly ruined by new ransomware, utterly baffled that it was possible at all. But when you're trying to use Photoshop without paying... well, shady stuff's still out there.