What problem does this address?

The font library currently uses a modal with tabs and tabs panels. In the view where you select from Google fonts, an infinite scroll is used. There are both accessibility and usability problems with this.

• As already reported, the focus is incorrect when the content inside the tab panel changes:
  #54431
• it is not currently possible to open the modal in any other way than using the "manage fonts" button in the typography panel in the global styles sidebar. This now blocks tasks like [adding a command to open the fonts]
  (Command Palette: add command to open fonts #54880). If this was handled as a separate page inside the Site Editor that could be navigated to, this would not be an issue.
• The infinite scroll is difficult to use, and this pattern has been discussed and has already been removed from other screens in WordPress. It should be avoided. Core trac #40330
• Even without the infinite scroll, a modal is not suitable for presenting this amount of content. You can also compare the size of the current font management modal and the media library modal. -At least with the media library the users has more than one option of where to manage their files.
• A full page has already been successfully used in the "Create block theme" plugin.

What is your proposed solution?

Create a rough draft with the font management as a Site Editor page so that the experiences can be compared and user tested.