It will take three seasons before ten Hag and Man United to bounce back
There are some quality but not quality enough to play for united
Having a good coach but the management should be supportive when hunting for good players
Three seasons is too much... only this season is ok for Manchester United to bounce back. They are already back to the big team they are. They won against Arsenal the league toppers, they won against Tottenham and won against Liverpool and drew Chelsea, they lost to Manchester City. This is a result of good team. What they need is to strengthen the team in January by buying defenders, a midfielder and a striker.
Manchester's appearance already looks better now. having spent quite a bit of money in the summer transfer window, they have a lot of improvement although still far from expectations.
however making the team better will certainly take time. as you said, MU just need to strengthen their team to be better in the winter transfer market, and be better prepared to compete with other strong teams for the rest of the season.
talk about champions may be too grandiose to see the current situation of MU. but that's what fans are expecting right now. they performed better and finished the season satisfactorily.