Back in the late 1980s I did a few tests at my workplace with one of those massive shoe-sized mobile phones — name and model number totally forgotten.
The first phone that I owned was given to my by my son (probably when he upgraded), and I can't find it online. It was an old Motorola with memory for 20 contacts (!), text-only display, probably dating from around 2003 or so. OS? Did it even have one?

It's main claim to fame is that it did phone calls and texts, and very likely it would still be working if it hadn't been dropped in water.
Then followed a couple of Nokia Symbian S60 phones (6120c and E-63). After Symbian was discontinued, I acquired an Android model and have used Android in one form or another ever since. iOS doesn't appeal (maybe because they are all priced out of my range) but I occasionally look to see if anything is happening re Linux phone development.