so many audio problems for audacity

I’m using an shure sm27, UR22 and audacity I get problems one after another

-When I connect my headphones into my UR22 and play the track, the playback is mono but when I plug it into my pc audio jack, it’s stereo.

-I have to turn up the gain at least 3/4 and headphone input 1/2 to get decent sound.

-when I plug my headphone in the UR22 and monitor like that it sounds way better and louder than the recording that was in audacity as it was more clear

How do I fix all of these problems at once? it’s so confusing