Balancing audio levels in a podcast worthy output is difficult!! A wonderful listener from https://lemmy.world recommended the fantastic Thimeo Stereo-tool, which is available as a VST, standalone GUI app on Mac/Windows/Linux or as a command-line tool for Linux on amd64 / arm64. A basic license is around $50, then you intergrate it with your audio workflow to taste.
First effort to run it on my laptop caused the machine to freeze up immediately, so GUI version was out. Frustrated, I went back to the product page and re-read that the tool is supported on the command-line for the Raspberry Pi 2 or better. Just so happens I have a Pi 4 available with an SSD boot disk.
Tools used to install
tmux/tmux over ssh over wireguard
Files transfers made using scp to and from the remote machine
Installation was straightforward, but usage requires carefully consulting each command-line option and preset from the manual. Total setup time, along with testing, took 5 - 6 hours before audio came out as intended. 💕 Success!! 🎆
30 minutes of raw stero .wav audio takes 2 - 3 minutes to process.