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 2020 Win Audiophile; [& 2019 Mac UltraPak]. Software: Cakewalk, Adobe Audition, Ozone, Encore; Win 10 64 Pro. Hardware: custom i7, 16 Gb; Roland Integra-7, Focusrite 18i20(2), TCE Finalizer, Behringer X-Touch, Adam sub & monitors.