Hello, the question is whether I can use fonts with the Open Font License, if not, which license should I look for?
You can use any font that you have the right to use (obviously). You should not include the font in the zip with your template, though, as this could lead to problems.
The Google Fonts are afaik all free to use so no problem using and showcasing them in your preview videos and referencing them in your projetc files. I’m not sure if it is allowed to include them, but even if it was I would not do it, you should just provide the link to the original font.
Mainly out of respect for the font creator, and to be sure to be on the safe side.