Harry Kane is playing for Tottenham for years and he is a famous player there, he is loyal to his team but because of the bad results he got in Tottenham, he is better to leave and find a team where he can achieve his goals.
Tottenham Hotspur's main issue is winning trophies; they will be at their best and still fail to win a single prize. Even the club's past managers, Anthonio Conte and Jose Mourinho, failed, so I can't think of any coach that is capable of saving the club because it's apparent that the problem stems from the boards and the players. I don't see any compelling reason why Tottenham Hotspur should have one of the best strikers in the English Premier League and still struggle to win a trophy. Harry Kane is the club's all-time leading scorer, and while he has not made his personal objectives public, I believe it is high time he tries a new chapter somewhere else.
It is interesting to know that Westham United has first Totenham to lift European Cup, this is because Totenham has no focus for any trophy. If they can do what Sevilla use to do it will be better for them. For instance when you see that people in Champions league are too strong, you crash out and go to Europpa and give your best.
When English Premier League is so strong, you focus on Fa Cup with all your energy. With this strategy you will be able to win just one cup for the the club and not to be sacking and employing coaches without vision.
It would be better to focus on each trophy instead of just one trophy, but of course, there is a possibility of failing from all trophies while doing this. It might be a good idea to evaluate this possibility and actually focus on one trophy. For example, this year West Ham United did it very well and managed to win the conference league. Who knows, maybe Tottenham will do this strategy next year.