When editing text in a CKEditor 5 text field (I haven't tested this in CKE4), in a custom block being added to a Layout Builder layout, and trying to link text using the CKE5 link button, the URL input field in the pop-up link modal is disabled (or is somehow otherwise blocking the ability to click into it).
Try this same procedure with Olivero -- or indeed any theme that isn't based on this one -- and the URL input will work as expected.
Active
3.30
User interface
This problem appears to be exactly as described in Using CKEditor 5 inside Bootstrap Modal causes interaction issues → . However, while we're using version 3.30, the problem does not appear to be fixed. At least, not for us!