You kind of have to look at this and say the coaching staff didn’t know what in the heck they were doing except trying to force fit a system (with lack of player talent in doing so). Your point about incorporating tight ends being a good example.
After a while, it got so bad that it was hard to decipher what was Tommy, what was scheme, and what was the players around him. Probably still all three, but you have to look at coaching. Probably the number one thing was a nearly no ability to build an O line in eight years.
I think perhaps the most promising thing Fran Brown has said is, when asked about his offense, he said “whatever they can’t stop”, which shows a willingness to be flexible and adjust