Hey @andrei - Just figure I would chime in from a previous comment about .json support for Unreal Engine 4 and 5.
I found a better way to get my tileddotmaker maps into unreal. While exporting as .json works via Paper2d you need to do allot of manual setup
That said I am using the wonderful Tiled Integration plugin. It simplifies stuff allot.
Here is what I did:
I got my sprites + tile sets + .TMX + .TSX then imported them all at once into unreal.
Keep in mind that you need to apply the Paper2D settings found in the right click menu to the Sprites + Tilesets.
Hope this helps someone.