I am going to attend my first game jam, so i am in doubt whether i can use the free assets from itch io store in this brackey's 2025 game jam
I believe you can use free assets from itch.io.
From the rules: “Use any engine or framework. You can also use assets not made by you, but make sure you have the proper license to use them and crediting is of course encouraged.”
If they are free assets, you should have the proper license (CC0). You can always link to the license in your credits as well.