I used to have a Nokia N9; great phone. But it didn't support WhatsApp and I was out on the loop on the WhatsApp chat all my other coworkers were in.
Then there's things like banking apps, flight check-in apps, food ordering apps, dating apps, etc. etc. Can you do without those? Sure, of course. But if I want to order food where I live then the only option is to use an app.
No platform will have any chance of any sort of adoption unless it supports some way of running those apps. There are options here, for example Jolla/Sailfish OS can run Android apps (no idea how well that works in practice; the latest update says it supports "Android 9, and the support for Android 10 is already nicely on the way").
It's a "vendor lock-in" ecosystem that's worse than the Windows lock-in of yesteryear IMO.
Since I don't really use my phone all that much I decided to "just use an iPhone" (because it's the only phone that's not huge), even I think they're really horrible.