Did you (and the other user) report this to IK Support? This forum is not a medium for technical support, the team will assist you directly via
https://www.ikmultimedia.com/contact-support/app Thank you
Edit - I just installed SampleTank on an iPhone 15 Pro Max running iOS 18.0.1 and it works, so definitely reach out to support to see what is going on in your case(s).