and even then there are some errors here and there. best to have someone around who has a little bit of knowledge to where to go look for additional info if things do not work or some lingo in the explanations might not mean what one things initially.

> How difficult is it for a non techy person to change their phone's operating system from Android to one of the non Android OS options?

Bloomin' difficult.

because on anything newer than 10 years ago the process definitely includes wiping storage of the device.

in some way its a security feature so no one can reflash your phone and get to your data. albeit i think its overly locked down in googles favor.

Save anything that can be saved (Cloud etc) to local storage and back it up to PC.
Assume you lose everything!
If Playstore can be installed (and then you lose the value of an alternate OS as that needs the Google Framework) most banking apps won't install.
The install / flash is now simple or impossible.

Generally, if you're using Android, your contacts, messages, etc are all stored by Google. You can't de-Google a device without losing them.

Your best bet would be to export all your contacts to a file, save that on a different device, do the same for your messages, then find someone who's got experience flashing firmware to phones to do the de-Googlification.. then import your messages and contacts back to the device.

It's not for the faint of heart.

If you de-Google your phone, but then sign back into Google for things like play store, chrome, etc, you've essentially re-googled your phone.