First part of this upload is how I found them if you want to follow and copy what I did np, but your save will be modified.
you do not need to touch your save !! the rest of the upload will show you the locations and some issues I had as I didnt know what to expect.
I hope you enjoy and kill some time with me
X4 Foundations | X4 [1.21] All Abandoned / Derelict ship locations in X4 Foundations
Be patient, probably still processing on youtube.