I use https://opentype.js.org/ to convert a font to path.
As you can see in https://caniuse.com/link-icon-svg all modern browsers support SVG favicon right now (88% of users globally). You can also download the PNG version to support wider audience. In the next version, I'll include support to download PNG version for all required sizes, with a sample html page and manifest.json file.
Also, support for dark mode is in my todo list.
There's a good article on this here https://medium.com/swlh/are-you-using-svg-favicons-yet-a-gui...
I just use https://realfavicongenerator.net/ which keeps things relatively easy.
https://caniuse.com/link-icon-svg
Supported by Edge, Firefox, Chrome, and Opera. Safari and iOS in a rather limited way, but you're still looking at about 70% of users with SVG icons alone. Not so sure how to look up if they're supported directly in the link element.
I just tested the "emoji" version on Chrome and it rendered some total junk as the icon, so I'm not sure about support for that either.
How usable are svg favicons nowadays? Do I still need a dozen link rels in my <head> with various icons in different formats/sizes? Currently I have one .ico file as rel="shortcut icon", 4 pngs in various sizes as "icon", 4 pngs as "apple-touch-icon" and 1 svg as "mask icon"