The Model 3 will be staying on the one it is on. That was mentioned because it is what got me to the point of actually looking for one for this TV in the bedroom.
The screen on it does have the 16:9 aspect ratio that I understand as the current expected ratio.
My understanding is that Roku models that attached directly via something other than HDMI are quite a number of years old and only available on the used market. Used is not a major turn off (the Model 3 was purchased as a used unit) but I do question how long updates will be available for the oldest ones that are still usable now. Then another consideration is that I have read of it can be tricky to get a HDMI converter to component, or whatever, to work reliably. Thus, my question to the group of what is the best way to go without breaking the bank?