Have you tried another brand? Seems like you are jumping from "I had a bad experience with one smart TV" right to "smart TVs are to be avoided".
I have a smart TV (of another brand) that I am very happy with, and while I don't really use the built-in apps, they are quite decent and – importantly – don't get in the way of me using the TV as a HDMI sink exclusively.
It even got native AirPlay support via a software update three years after its original market launch, something I'd absolutely not expect and was quite pleasantly surprised by.
I have a smart TV (of another brand) that I am very happy with, and while I don't really use the built-in apps, they are quite decent and – importantly – don't get in the way of me using the TV as a HDMI sink exclusively.
It even got native AirPlay support via a software update three years after its original market launch, something I'd absolutely not expect and was quite pleasantly surprised by.