If I understand correctly your problem, the simulators you can use depend on the minimum deployment you've defined for your app.
Select the app in file navigator panel of Xcode
select Targets
select general
Then set the minimum deployment to iOS 18 or lower if you want to use such simulators.
Then, in the top bar of Xcode window, select the simulator as usual.
Topic:
Developer Tools & Services
SubTopic:
General