Florian Wirtz seems like secured for Leverkusen for at least next season. Normally it wouldn't be much possible but Xabi Alonso effect changed everything for Leverkusen. They started to believe in themselves to achieve any title available. 
Therefore I also think Wirtz doesn't need to leave already now. He is only 21 years old as well so there is no need to rush while doing wonders with his team.
But in the summer of 2025, it seems like it will be very difficult to keep him. Real Madrid and Barcelona are already monitoring him according to rumours. As long as Leverkusen doesn't win the Champions League title I don't think he would stay.
Bayer Leverkusen are inform and we should expects more from them next season and addition of young potential talents like Florian Wirtz who is listed among the best players in Bayer Leverkusen and play an important role in providing main assists for Bayer Leverkusen to win the Bundesliga title with unbeaten and also netting top class goals. With more time, we will start seeing top clubs coming for him as prime target, remember these clubs will always settled for the very best players inother to meet up their targets. Therefore I also think Wirtz doesn't need to leave already now. He is only 21 years old as well so there is no need to rush while doing wonders with his team.But in the summer of 2025, it seems like it will be very difficult to keep him. Real Madrid and Barcelona are already monitoring him according to rumours. As long as Leverkusen doesn't win the Champions League title I don't think he would stay.
The big clubs are gonna come calling, no doubt. It simply functions in that way. We must, however, now relax and enjoy the ride. Wirtz is going to be a superstar, and this Leverkusen team is the genuine article. Though where he ends up is going to be crazy, he is currently the lifeblood of this amazing team. Anyone knows, really? Perhaps the following season they will repeat as champions. You will hear a lot more of the name Wirtz in any case