Extremely slow progress pasting audio and project file continuously increasing in size?

Hi guys, I am trying to edit an interview in Audacity. When cutting/copying and pasting bits of the interview to a separate track, Audacity stops and takes multiple minutes to paste each section regardless of length.

I’ve turned off Smart Clip, and tried many different things but nothing seems to make this any quicker. Also, the project file is continually increasing in size with every paste (now up to 6.8GB) which seems ridiculous, as though each paste requires copying the entire 40 min audio file again rather than pointing to the one audio file as it should.

Any help would be very appreciated. Cheers

That only speeds things up when you paste audio to another Audacity window.
Within the same Audacity project there is no escape from Smart clip lagginess .