The Ready State Virtual Mobility Coach is like having a virtual Kelly Starrett in your pocket.
If pigeon stretch is a no go try this banded hip external rotation mobilization instead:
In terms of the couch stretch start with the partial movement with the torso at 45 degrees. From there work some end range isometrics. Do a few cycles of contract relax at that range and in time as mobility improves you can work your way a Supple Leopard position with the torso more vertical. Also recommend throwing in some quad smashing as you are doing the couch stretch to help open up the front of the hip. Here is a solid routine to follow show the combo of couch stretch + quad smash and seeing how you can progress to a more vertical torso: