Need Advice Please wifi speed extender

Thanks for looking...briefly we have comcast cable 200 mbps service. Plugged (wired) a pc into the ROUTER (not the modem) and ran a download speed test. Then unplugged and ran another WIFI download speed test next to the router. Wired= 215 mbps,  WIFI=75 mbps.

The problem we have is a firestick in a room through 2 walls and a TV cabinet about 65 feet away is receiving only about 25 to 30 mbps (same speed test, same pc as before). The result is that the TV app freezes, glitches and dumps out to the firestick home page. The firestick says it has an excellent signal so does that mean the download speed is to low? The TV streaming company rep said 25 to 30 is too slow.

With 200 mbps coming in, is there a way to get 75 to 100 mbps in a room 65 feet away? (without replacing everything...lol)

I'm guessing if the PC is recording a 215 mbps wired to the router...that means the router is receiving 215 from the modem...right?

Just in case that is not the case...here is the modem: Motorola SB6141

Range extender??  Thanks for any advice.