Export to MP3 is distorted but WAV file is too large

Everytime I export as an MP3 my music gets distorted (podcasting, music+speaking). I know WAV files are best but they are too large to upload onto squarespace. When I would usually export as MP3 there was NO distortion, even earlier today it worked fine multiple times but now it sounds like my podcast was made by a robot.

Any suggestions/advice ?

Leave 1-2dB headroom before exporting as MP3, as that process can amplify by 1-2dB causing clipping distortion on the MP3. E.g. normalize your Audio to -2dB, then make the MP3 version.

Using very low bitrate MP3 can be robotic : lower bitrate → lower file size (but more computery).

Apparently SquareSpace allow you to link to an audio external host, (SoundCloud?).