Would you be kind enough to recommend preferably a free version of a software that applies that function ?
There are several free software options that you can use in combination with Ax Crypt to add 2FA or access control functionality to your encrypted files. Here are a few options:
1. Veracrypt - this is an open-source encryption software that works similarly to Ax Crypt but provides additional features such as multiple authentication factors and access controls.
2. AxCrypt Premium - while there is a free version of AxCrypt, the premium version offers some additional functionality such as password-protected key sharing and two-factor authentication.
3. Cryptomator - this is a free, open-source encryption tool that works by creating encrypted virtual drives. It supports two-factor authentication for additional security.
Keep in mind that these tools may have different levels of functionality and security, so be sure to thoroughly research and compare the options to find the one that best fits your needs.