Media Encoder 2021 15 stuck Loading Importer QuickTime Bundle on Big Sur

Recently updated OS on MacBook Pro (2018?) to Big Sur. Since then, when Exporting to Queue from Premiere Pro 15.2, Media Encoder 2021 (15.2) gets stuck on the splash screen saying "Loading Importer QuickTime Bundle". Trying to reinstall Media Encoder 15.4 using Creative Cloud desktop app but the download/install is extremely slow (over 1 hour).

I'm seeing multiple threads about Premiere Pro getting stuck Loading Importer QuickTime Bundle. Is there a solution? Has anyone had issues with Media Encoder + Big Sur?