AirPort Time Capsule Issues With Repeater

Hey everyone,

So I added a smart garage door opener to my detached garage and there wasn’t enough signal strength to operate it so I purchased a WiFi repeater (TP-Link RE205). What I’m noticing is that whenever I plug in the WiFi repeater, the RSSI that I receive from the main router (AirPort Time Capsule 5th Gen) is going down quite a bit. The RSSI goes back up when I unplug the repeater. I also tried a Netgear EX3700, but am having the same issue. I know the Time Capsule is discontinued, but I’d rather not buy an entire new router. Any tips? Thanks!