If they want Colts teams then there should be a full pyramid and they start at the bottom of the pyramid. Living down South the premier leaugue can play their u23’s in the EFL Trophy. None of them have won it yet. The closest to the final was Chelsea who got beat by my local team Lincoln City in the semi final a couple of seasons ago. Personally I’m not keen on that as they can field players who played in the champions leaugue the week before. There should be no B teams. If they want to develop players then loan them out to teams at the bottom to get experience.