It seems to me you are taking a big risk. Some considerations:

> Cryptomator

Much security is poorly implemented; you can't count on it being effective. Even Apple, which takes security very seriously and has world-class talent and enormous resources, fails to implement security effectively sometimes (as in the OP). Can Cryptomator do better? Find the most respected - by professionals - security solution you can.

And on a device with many other functions - all the things you use your phone for - you risk all sorts of security holes in every function of app you use. And what happens to the data when your phone is backed up? Store the data on a single-purpose device.

Also, on an Internet-connected device, you make the data potentially accessible to the entire Internet. Use offline storage.

Bringing the storage device with you everywhere is asking for a mistake on your part - losing it, etc. Hide it someplace.

> or legal access

Ask a lawyer.