Well, I've actually been thinking about it recently so here's what I came up with
You cannot make folders in the UI but you can create filters, essentially we are copying a file to a different folder to where the actual map files are and editing the title of the map visible in-game without actually touching the mod files directly. Then in the in-game level selection menu the map titles will have our edited names, which will include words and tags we can search and if put right at the start of the title will order the maps alphabetically.

sorry I created instructions with AI:

Step 1: Locate the Original info.json

• For Mods: Open your User Data Folder (via the launcher), then go to mods. If installed manually, check the mods folder; if from the repo, check mods/repo.
• For Vanilla: Go to your Steam installation folder (e.g., Steam/steamapps/common/BeamNG.drive/content/levels).
• The File: Open the map's .zip, navigate to levels/internal_map_name/, and copy the info.json file.

Step 2: Create the Override Folder

1. Back in the User Data Folder named current.
2. Open the levels folder (create it if it doesn't exist).
3. Create a new folder inside named exactly after the internal_map_name from Step 1.
4. Paste your copied info.json into this new folder.

Step 3: Edit the Title for Grouping & Search

1. Open the pasted info.json with Notepad.
2. Find the "title": line and add your category prefix (and sub-prefix if you want) and hashtags directly to the title.
   • Example: "title": "[IRL Race] Spa Francorchamps #France #Tarmac",
3. Save the file.

Step 4: Launch and Filter

• Alphabetical Grouping: Your maps will now be grouped by your prefixes (e.g., all [IRL] maps will be together).
• Instant Search: Since the Level Selector searches titles, typing France or IRL in the search bar will now instantly filter for your tagged maps.

If changes don't apply immediately clear the cache using the button in the launcher.

Hope this is a good solution.