"Google slide" is not a game engine, it is a program to create slide-based presentations, where it is possible to extend the functionality through certain commands, which I imagine is how you created your "game".
It is similar to creating a game using a spreadsheet program, you cannot export a game, you can only save the presentation as a file, the problem is that the file can only be played using a compatible tool, that is, that person must download the file of your presentation, upload it manually to google slide or a similar program, such as office powerpoint and run it from there.
Just because it is possible to create something interactive with this type of program does not mean that you can create a game and expect it to be played on Itch, you will have to use a game engine.
Surely your game will be an interactive story or a kind of visual novel, if you have a PC, you can try Renpy.
If you don't have a PC and only have a tablet, you can try twine, it is an HTML engine for interactive text games (you can also use images) and it could work for you. There are many games on Itch based on Twine.