Option to change page header font about customizable-page-header-buttons

[kometenstaub]

I think the best way to do this is by adding a CSS snippet.

On desktop, the system fonts can be accessed, but for mobile all the theme developers include the fonts as base64 string in the CSS.

With a snippet you can include the font you want to use:

All you have to do is take your font file and upload it here: Transfonter.org. Toggle on Base64 encode and hit convert. It will generate a kit for you with a style.css file. Open that file and you should see an @font-face for your font. Add this to your snippet.
From Chetachi on Discord with small changes

And then add this to the snippet, just change Inter with the name of your font:

.view-header-title {
    font-family: "Inter";
}