Ciao Niccolò,
Possible:
- If we talk about Google Font - you can set it thru Helix Template - Typography settings
- Any font (also Google Fonts) you can add by custom CSS if you have different template which doesn't have similar options (1).
in both cases you can set selected font for selected HTML tags or/and classes also from SP Page Builder. It's a few minutes task. Nothing complicated, basics.
Example (one line, font for whole site)
body, h1, h2, h3, h4, h5, p, li, a, span, i, strong { font-family: Arial; }
just use in template custom CSS section or custom css file - just read template documenation.
Of course disable Google Fonts in SP Page Builder Options if you don't use them.