Similar issue
Submitted my app for review, got rejected due to a backend bug
Fixed backend issue, resubmitted the app. During this step somehow the earlier linked subscription got removed. Review team rejected the app because subscriptions were missing causing UI issue
I couldn't find a way to relink subscription so I created a new build and linked it in the review page
The "In-App Purchases and Subscriptions" section is still not present anywhere on the page
Subscription pages says
Your first subscription must be submitted with a new app version. Create your subscription, then select it from the app’s In-App Purchases and Subscriptions section on the version page before submitting the version to App Review.
Once your binary has been uploaded and your first subscription has been submitted for review, additional subscriptions can be submitted from the Subscriptions section. Learn More
I don't want to delete my subscriptions because I can't recreated with same product IDs which are linked in my IAP code
I am stuck and it has been few days with back and forth :(