I bought an LG OLED CX this past November. I was planning to hook a roku up to it. My experience with smart tvs in the past has been hugely underwhelming to downright unusable. But I've been more than happy with just using the apps on the LG tv. Your mileage may vary, but I have a good picture quality and I'm pretty happy with the remote. It allows me to program the keypad to hard-press them to launch an app of my choice. Additionally, they have their own channel offerings similar to Pluto.
I have heard great things about the Shield as well. That is probably the closest you can find to without building your own HTPC.