trust me , I'm not thrilled with the idea either .I wouldn’t recommend using the Roku mirror feature. It worked well initially but if you join a game in progress it won’t let you re - start the game , it always went straight to the live action.
I have available hdmi slots so buying 1 amazon firestick on the dedicated t.v that I watch sports on is likely where I'm headed . I think they are around 40-50 bucks so its not like I'm buying a sattellite receiver