If the same records repeat in the Leverkusen then this will be a disaster for Eric Ten Hag's career. Bayern Leverkusen's experience with Eric Ten Hag should be admirable so that the coach can avoid further criticism.
When Ten Hag first joins a team, he usually does pretty well. But after a while, he starts making changes that I think mess up the good foundation he built early on. Like signing overpriced players who don’t really deliver and end up being a waste. Hopefully, he learns from that and just sticks to the original game plan to take the team to the next level.
Ten Hag must have learnt his lesson from United and won't want to repeat those. When he was the head coach of Ajax he had good records, he won three Eredivisie titles and two KNVB Cups even at United where he had a struggling career he won the EFL and FA cup. I believe he should have studied his predecessor Xavi and his tactics so he knows how to strategize for the coming season heading his new team Leverkusen.