No worries at all. You’re correct that you would need to target an element with CSS and set the font that way.
This isn’t the best practice, but you could try something like this:
.bens-class {
font-family: [your font], sans-serif !important;
}
The important tag will override any other styles. Then, in the page builder, for any module that you want to use the font, you can add the class bens-class in the advanced tab.
And or, the plugin above might be the easiest route. 