Parental control is a also a hot buggy mess on iOS currently. Our daughter has an iPhone with parental control set up and a bunch of apps that are whitelisted regularly refuse to start at random moments (blocked by parental controls). We hoped that iOS 26 would finally fix it, but nope.
It doesn't really matter, both phone ecosystems are a mess, but in different ways.
I screen her emails with her consent, very easy to do with Fastmail that imports her Yahoo mail into a folder she doesn't see and then I move okay emails to her inbox.
It's a good idea, but terrible execution.
Once I set up an Android phone for her, I will publish what I did to help others.
I recommend getting an Android phone (there are cheap Google Pixels out there) and try to sideload an app. Also browse the web a bit without an adblocker. I'd be surprised if by the end of the experiment you thought that sideloading is the reason their grandma's phone is full of crap.
It's not all good or bad, there's a security issue with side loading, as well as shovelware on the play store. However, there is no world where I would argue that these justify limiting consumer grade hardware to walled gardens.
If you do go for a smartphone, my experience tells me that there's no difference between Android and iOS. The biggest sources for shady apps are the Google Play Store and Apple App Store. Shady stuff on the web can be easily defeated using an adblocking browser, which is essential for older relatives.
With a well-supported hardware configuration and a working web browser, even a non-techie may have a more stable experience than they would with Windows.
That has as much to do with the decline of Windows as with the ascent of desktop Linux, but still.
Bulletproof, immune to all the apps and malware. She couldnt break it.
A Linux install that meets the basic needs of the user is perfecto!
Less so recently just due to time constraints, but I'm generally the technical person in my family group, and I've lost enough touch with Windows that troubleshooting it is increasingly difficult. If they need me to 'format and reinstall' they're getting Linux unless they have a very specific need that only Windows can cater to.
You know, they are adults and have free will and do want a smartphone like everyone else to use Whatsapp, read the news, search things on Google, etc.
Hell, my 95 year old grandma convinced a nurse to install TikTok on her phone because she saw her using it and also wanted to try it. It's not like we can isolate them from the world
Some things are actually worse on the iOS side. It took years for Apple to catch up with spam and scam calls/SMS detection.
Plain Google search is still the main vector of scams, I eventually set up NextDNS on her devices.
How incredibly sad this fact is. And even sadder all the second-level implications about how it got to this point. And then sadder still that there is unlikely anything done about it in the foreseeable future.
This is one of the cases in which giving them an iPhone with its walled garden has great benefits. You can also setup parental control on top of that already locked down ecosystem.