I have about the same internet speed you do, for standard definition, it is usually fine.
I used to move my Roku from the Bedroom to the living room, I bought a second one a few months ago to make life more simple. If you want to run two TVs at the same time you will need two boxes, on the other hand with your internet speed, you will not be able to support two streams at the same time, so you could get by with one, moving it to where you want to watch.
That’s the speed that I have. I gave up watching because of all the freezes. ATT will tell you you need to upgrade ($).