For smart TVs, I'm a fan of the TCL Roku TV series. A lot of other brands have home-grown, half-baked "smart" interfaces with limited streaming-service support, but the Roku TVs work the same and have the same broad service support as standalone Roku devices.
There's a 40" model right at $199 USD online, though I think it's a 1080P model. I paid a little more for a 43" 4K model, and we're loving it so far. (That said, you really don't need 4K resolution at 40" anyway. The 43" just happened to perfectly fit the space it was going into.)