There is a difference between the server API limit and the UI search page limit. The API call to /hubs/search?limit=30 is applying the results per hub. i.e. 30 artists, 30 albums, 30 tracks, not a global 30. Look at the size attribute for each hub, it can go up to 30 results.
The Plex Web UI search results page is then cutting down all the results (which there are more than 30) down to 30 total results. This is purely a Plex Web UI issue and not a server API issue.
You can clearly see the difference between the hosted Plex Web (Version 4.86.1) and the local Plex Web (Version 4.84.1) search results page (/search?query=<some text string>). Both versions of Plex Web use the same server /hubs/search?limit=30 API query. The older search results page just shows all items from all hubs (still limited to 30 per hub), but the new search results page cuts it to a total 30.
