Man United has already signed Rasmus Hojlund, so it can be assumed they won't be going after Harry Kane anymore. His performance will indeed be questioned because he is not yet considered a world-class striker and competition in the Premier League is clearly much different from Serie A. But I think Ten Hag must have had a reason for being so insistent on bringing Hojlund to Old Trafford.
I think Hojlund is a good signing and Ten Hag probably thought it was too risky to sign Harry Kane from Tottenham. In terms of quality, Kane is indeed better than Hojlund, but spending up to 100 million euros for players who are entering the age of 30 is not the right move. Kane could have stayed at his best playing level for the next three seasons, but on condition that he didn't get injured. Of course this is what underlies Ten Hag not insisting on recruiting him because Kane cannot make a contribution in the long term.
On the other hand, Hojlund who is only 20 years old, is cheaper than Kane and has better development potential. And of course the risk of losing in recruiting him is not comparable to Kane, if Hojlund cannot live up to expectations United can easily let him go to another club.