Actually, one idea could be to have a look at the old builds that we have on TestFlight! They will expire sooner or later, but here’s an idea:
Please visit this link and register for testing: Join the Navigraph Charts beta - TestFlight - Apple
This will give you access to an old version of the app (8.20.0) for a limited time, which I assume used to work for you.
I will also upload the latest version, as this platform allows us to collect crash reports! This step will take some time however since Apple will need to review this release first. When they’re done, you should be able to download the new version from TestFlight and we should be able to gather at least some more information about your situation!