I am also currently trying to germinate some seeds, which were sold as Diplopterys cabrerana.
Mine are looking like yours...
The seeds I have look somewhat like Diplopterys longialata seeds, but to be honest, I can´t tell, since I am not an expert.
I was successful in germinating one of these seeds a year ago.
As stupid as I am I dug up the seed, to see what is going on and hurt the root, by doing so.
This time I put the seeds for germination in sphagnum moss, and placed them on a heat mat, after soaking in a glass of water for 2 days.
I don´t have much hope that they will germinate, they seem to be harvested in September 2021, maybe they´re too old?