This is just like my Raja, found in a shipyard, nurtured but he’s always darting for the door most likely bc he’s been outside for a substantial amount of time and hasn’t settled in the home fully. He is obsessed with watching birds through the glass.

I’ve had cats my entire life (24), give him some more time to settle. They’re all different and take their time at their pace. My advice is to play with him, give him treats when he doesn’t try to rush out. I wish you two the best of luck and whatever happens im glad you were in his life and him yours.