You missed one step. that is to copy apk file in the downloaded directory to phone and install it in phone. only then Pc will establish a connection to phone.
c:\an>gnirehtet run 2023-10-26 16:19:10.327 INFO Main: Starting relay server on port 31416... 2023-10-26 16:19:10.327 INFO Main: Checking gnirehtet client... 2023-10-26 16:19:10.332 INFO Relay: Relay server started 2023-10-26 16:19:10.440 INFO Main: Installing gnirehtet client... Performing Streamed Install Success 2023-10-26 16:19:14.998 INFO Main: Starting client... Starting: Intent { act=com.genymobile.gnirehtet.START cmp=com.genymobile.gnirehtet/.GnirehtetActivity } Error type 3 Error: Activity class {com.genymobile.gnirehtet/com.genymobile.gnirehtet.GnirehtetActivity} does not exist. why?