This is very solid information, Noel. Yes, it is critical to avoid compressing a compressed file. While I don't use SoundCloud, I have encountered severe artifacts on YouTube. My video guy would make the original file as large as YouTube allowed before it would employ a worse compression level.

Radio stations can really destroy the quality (and dynamic range) of a song also. I have learned not to try to out-think a radio station, because whatever they do will mangle the sound anyway. The only thing you can do is what you say, stay in a non-compressed mode as long as possible.
BIAB 2021 Win Audiophile & 2020 Mac UltraPak. Software: Studio One 5 Pro, Adobe Audition CC, Notion 6; Win 10 64 Pro. Hardware: custom i7 16 Gb; Roland Integra-7, Presonus Studio 192, Presonus Faderport 8, Royer 121, Adam sub & monitors