The one feature I like about the smart TV is support for DLNA

Yes, a nice feature that even early "smart" TVs had. It could have stopped at that and everyone would have been happy.

But today's smart TV's loaded with ads; unnecessary bloat; “shortcuts” to services you have no intention of ever using; massive user tracking; and complicated firmware/software that can render your TV useless, have become the real problems. It's the enshittification of hardware that really was just fine being "dumb".