We have these limits for a reason, if you aren’t familiar or capable of optimizing your game for browser play then we recommend offering it as a downloadable game.
https://itch.io/docs/creators/html5#zip-file-requirements
Based on what I can tell about your game from the screenshots you provided on your page, 1GB seems abnormally large, which suggests you are using uncompressed or un-optimized file formats, or potentially including additional assets that you game does not even use.
Thanks