I think he was a bit unlucky tbh. He had 3 winning seasons and 1 losing season in Indy (the year Luck retired just before the season started).
Everything really cascaded downwards for him in that final game of 2021 when Carson Wentz melted down and the Colts blew their chance of making the playoffs. It felt like the whole narrative around him changed in that game.
It would be a job well suited to someone like Meyer or Hackett or McDaniels who could set themselves up financially if they got a 6 or 7 year contract which would have to be settled on dismissal.