You may check “Compress File” option in Save & Load settings in Blender Preferences (Edit - > Preferences). It will help you to reduce actual .blend size when saving it.
Another thing you could do is to check “Show Hidden Files/Data-Blocks” in that same tab. I’m not sure what it does, but maybe it would help you as well.
I just found out that I dealt with the similar question here, some moons ago (see here), there’s an add-on called “Atomic Data Manager” which could help you to understand why your file is so big and what you can remove from it in order to make it a bit lighter. It’s free. Here’s an official link to download it.
Hope that helps
Cheers,
Sergey