Great job on creating and finishing a game!
It's cool that you were able to make 2D and 3D aspect in the game.
With the asset packs you get a lot of files which make your project very large.
You probably don't use all the files.
An easy way to initially reduce the project size, is to:
1. create a new blank project
2. migrate over the map from your current project to the content folder of the blank project. This way only the related files which are used will be migrated. So you'll only use the files that the project needs.
3. Settings such as the project settings won't be migrated over. So, you wanna check these settings. This includes settings like the default game mode and map.
Good luck on your gamedev journey!