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.
Florian Wirtz is one key frontline for Bayer Leverkusen and Xabi Alonso will not take things likely with his opponents next season. Bayer Leverkusen won the Bundesliga title with unbeaten run, they didn't record a loss and we know they're the best German club this season, surpassing Bayern Munich and Borrusia Dortmund. 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 have other plans to meet up, winning the UEFA Champions League title is their target but they should ensure they're having one of the best competitive squad because this is no newbie title but meant for top clubs.