No conclusions can be made so far on Eric Ten Hag’s new managerial role in Bayern Leverkusen. Just because he had a poor form at Manchester United doesn’t mean he’ll have the same at Bayern Leverkusen. He did well at Ajax and that was what gave him the job at Manchester United which did not really favour him in the end. He may be lucky after signing at Bayern Leverkusen to even perform much more better than he has ever did in his entire career.
Kompany managed a team that was relegated and went ahead to manage a team and won them the league title in his first year of managing them. In this case, we might say the teams in questions are different and also the strength on the team could help him out. He was been criticised just like ETH is now, so if he can pass through those criticism and come out victorious, I think Eric Ten Hag can also make that happen with good coaching from him.
Kompany when he was manager of Burnley in the Championship was totally different from the Burnley in the Premier League. You forgot to add that he was the person to bring them out of the championship to EPL with a marvellous performance. You can't compare that very team to the other teams in the EPL, so I really don't agree with you on the narrative of coaching a relegation team then going on to win the league the next season with another team. Kompany would have still struggled if it was Wolfsburg he was in charge of and not Bayern Munich.