Since the first version of this looked (reasonably) unstable, I‘ve decided to buy the 13€ Scubapro Gorilla QR set which seemed to have the same attachment as the xDeep.
The Scubapro attachment is firmly secured to the Mask and it seems like it was made for this.
So if anyone else thought about it:
Scubapro Gorilla QR Buckle Set is compatible with xDeep Radical Frameless
Because I‘ve missed the Scubapro click-system for their mask straps I did this:
We randomly found an broken Scubapro Zoom mask with that system on the seafloor at 30m so I decided to sew it off and fix it at my XDeep mask.
The piece has now two tiny holes with two zip ties attached to the normal anchor/suspension point of the Mask so I dont feel like it is going to come off that easy.
Now it is compatible and I can finally use my comfort straps again!
Edit:
Please dont think im stupid for doing this. I just had the idea and if it wasnt 2x zip ties each capable of withstanding about 8kg of force attached to about 8mm of hard plastic, I would never even think about doing this.