Yes, I tried it just to si if that was the answer.
Everything seems to work alright, and the results seem coherent! This "workaround" lead to coherent results, so I intend to think that this method works. It is good to know, and hopefully will help future or current users, thanks a lot!
The only remaining issue is why by applying the terrain correction a whole part of the observed scene disappeared... Another image to explain this small issue:
I'll try by taking a larger scene and also more SLC files, as I just worked with twelve to test the workflow.