I don't think Real Madrid will complete Harry Kane's transfer if Tottenham set such a high price for him. I think Real Madrid would likely complete Mbappe tranfer for the same value if they were willing to spend that amount on a striker. But instead of buying an expensive striker, Real Madrid have an alternative where the unexpected Joselu has become Real Madrid's latest signing as a striker.
Real Madrid are a smart club and they have a policy to avoid signing too long contract with old players. I don't think they will break their policy to sign a contract with Harry Kane and even have to spend not cheap transfer cost for that striker. It wipes out all terms in their policy which has been applied in Bernabeu many years.
Between Harry Kane and Mbappe, it's wiser to invest money into Mbappe, not into Kane. Kane is older than Mbappe and even Kane is a world-class striker, he has never played beyond Premier League. Will he be able to adapt to La Liga style? Who knows? At his age, two failed seasons will be like an ending for his career.
Jesulu may only have a short-term contract with Real Madrid as he was the only alternative being considered after Real Madrid lost Benzema. If Real Madrid don't find their best new striker, then they might do it again in another transfer market while following developments on Mbappe's situation at PSG.
Joselu is young and just scored a win goal for Spain to beat Italy in Nations League. However, he is far to be considered as a world class striker. He can improve his skills like Kane did years ago and became a world class striker but I feel he won't be able to do this if nothing really big will change his career.
I am doubtful that Joselu will be able to replace Benzema for Real Madrid as there is big differences in skills and experience of two players.