If you haven't already followed this guide, I suggest you do.
https://docs.unrealengine.com/en-US/Engine/Performance/ReducingPackageSize/index...
You still may need to cleanup a bit on your own but hopefully this makes that easier.
Viewing post in Packaged game very large!
Thank you! Yes I had seen that in fact it did help bring from huge sizes down to a... more manageable (?) 980MB ish game. I just submitted it to itch.io as a "downloadable" rather than an HTML game, which will probably discourage many - if not all - from playing it, but at least I'm within the deadline and I will try in the next few days to work with itch.io support and publish it as a brower game even if it's > 1GB.