Sadly that's all there is at the moment. I've emailed itch to ask for more hosting quota (To allow players to download directly from itch) but I haven't received a response yet. Once they give me enough space to upload the game here, that will become an option.
I'm having issues with both of these too unfortunately.
Would it be possible to try a multi-part, split archive approach? I think the main issue for me is that the file is just too large to get in one shot without failing on either hosting service.
It would be one way to work around the Itch file size limits to be able to host files directly, or make the downloads on Mega/Google more likely to complete successfully by breaking it into multiple smaller files.
7-zip (https://7-zip.org/) is one free cross platform software option that can handle creating split archives in multiple parts, as well as combining them back together.