I mean if you worry about spying just don't connect smart TV to internet, but yeah, the interface will be usualyl slower than dumb TV.
If you are frustrated by outdated software nothing stops you from plugging whatever Android stick into HDMI port, that's what I did with my dumb "smart" TCL with extremely locked Android without app store, without side loading (no it's not possible unless you wanna disassemble the TV and hardwire it) and with Youtube regularly crashing.
But why would you want TV without speaker, that's what makes TV a TV, if you dont want even speaker then it can be hardly called a TV, that's like calling phone something which can't even make call.
Btw. there are always projectors, where it should be better situation and you are also not limited by size.