How can I filter a noise with pattern type in audio?
Simple idea: let some pros do the work. Send the audio through a cellphone to another one via a WhatsApp, Duo or whatever voice call app, even classic network call works, dealer's choice. The noise reduction algorithms in cellphones are designed to do exactly what you want to do. Reduce noise while conserving human speech. The outcome will depend to some degree on the market, the phone's firmware was designed for. US customers like it, when the background noise is cut out completely, accepting some degradation of speech. European customers prefer more naturally sounding outcomes with some noise left.

I think this would be worth a shot.