Hello dear Sepi,
most likely will the actual version of the Strida ball joint socket fit your bike; at least the spare part numbers of version 3 and 5 are identical.
I mean you should ask Strida Spain first;
https://www.strida.es/
You can order online, for example, here;
https://stridacanada.ca/product/strida-ball-joint-socket/
of course I could send you the part from Austria, too.
Kind regards,
Chris