How can I decrypt a file without cryptomator?

I’m trying to future-proof a folder of journal entries and other important docs and was wondering about the survivability of a format like cryptomator. Are there other ways to decrypt these files using non-proprietary means? Lets say windows or mac or linux doesn’t support Cryptomator in 15 years – will there be a way to get into a vault?

Just like any other encryption solution:
You need the software that has encrypted the files to decrypt them.