My wife hates every smartphone that is currently in the market. They are all too huge for her. She has an iphone SE which was the best compromise at the time, although she still finds it big. She doesn't want to get a new one, because there is nothing on the market of that size. She doesn't use most the smart features. She only uses it for chat with family and friends and getting email notifications (and reading them, but never replying on the phone). She also uses it as a camera. And calls, including video calls. This might be a solution, although for some reason they say "no email app". I'm hoping you can add one later.
And then as a child's phone to keep them off social media, while also having a chat app to actually communicate with them.
Even for me, it's been some years too that I've been thinking that I don't really need a smartphone. I mostly need a device that I can use to make calls and that I can use as a hotspot for connecting other devices such as a laptop when I need to.
The keyboard will definitely not be an issue. I'm old enough to remember teens using those kind of keyboards typing blindly in astonishing speeds, even without T9.
Lack of 5G might be an issue.
The price is steep. I'm not sure if that is going to be a problem.