Lifetime Mac

Buy once instead of Boxcryptor

Ways out
2apps that do the same jobs
Cost nothing
2freeware or open source

Read the catch on each before you switch. A one-time price is not automatically the better deal, and we say so where it is not.

2 apps
CryptomatorClient-side encryption for files you keep in someone else's cloudFreeOpen source

Free on the desktop only — the iOS app is a separate €29.99 purchase

VeraCryptEncrypted volumes that open on macOS, Windows and Linux alikeFreeOpen source

Needs macFUSE, a system extension that can lag weeks behind a new macOS release