Hey Pandako first of all thx for the extension.
i just wanted to point out that this guy here did a pretty good job at detecting things from Tiled:
https://willianholtz.itch.io/tiledlink-for-gdevelop
it detects even slopes,layers,items ecc.
the only downside is that you can't check collisions "inside" the map (between objects bcs always in collision) bcs it didnt received update for new GD.
I believe in your hands this could became the definitive tool for Gd/Tiled and a great feature for the community.
If you have some time..pls have a look at it.