You shouldn’t go back and edit old forum postings.
Nobody will see the corrections.
We work forward down the message list only.
You hit one of the sure-fire ways to kill an audio production (#4).
Effect > Noise Reduction only works on sounds that never change such as microphone hiss or wall power hum.
Effect > Compressor brings the background sound and the performance closer together, so that’s the exact opposite of what you want. Even worse, Compressor can make it so the other tools, filters, and effects stop working.
Effect > Noise Gate is the answer for fixing this in post production. It’s not automatically adjusting and can be tricky to use. It depends on the main recording to be perfect, so the main voice can’t have problems of its own.
What’s your microphone? You might need a hyper-cardioid type instead of a regular directional microphone. Also a possibility is a shotgun microphone.
These are very directional and will ignore sounds coming in from the sides. Also very expensive.
You can also help a lot by making a mini studio. This is the Kitchen Table Sound Studio.
https://forum.audacityteam.org/t/too-compressed-rejection/52825/22
There was a video made by someone who got good sound isolation by just crawling under a heavy blanket while he was recording. You have to be good at not breathing to make that one work.
He did it to avoid room echoes, but that helps with environment sound, too.
https://www.youtube.com/watch?v=sq2yoVwpRs8
Is there a goal? I don’t think we ever hit a goal in there. Are you producing a podcast? Audiobook?
Koz