Depending on what country you are in it could definitely be dangerous. It could be dangerous even having them on an external drive if it is not properly encrypted. If I were you I would look into veracrypt for security. I have not explored the limitations of veracrypt with linux operating systems but you should be able to make a "main" encrypted system and then a "dummy" encrypted system. Essentially if you input password 1 then the dummy system will be loaded and your main system will remain hidden as long as you do not reveal the password to it.
Here is the veracrypt website if you are interested.
https://www.veracrypt.fr/ - main page
https://www.veracrypt.fr/en/Downloads.html - download page
And since you have mint and veracrypt doesn't have a custom made installer for mint(Although the generic installer SHOULD work) here is an old post from 2018 discussing how to install on mint if the generic installer doesn't work.
https://forums.linuxmint.com/viewtopic.php?t=275495
Here is the veracrypt website if you are interested.
https://www.veracrypt.fr/ - main page
https://www.veracrypt.fr/en/Downloads.html - download page
And since you have mint and veracrypt doesn't have a custom made installer for mint(Although the generic installer SHOULD work) here is an old post from 2018 discussing how to install on mint if the generic installer doesn't work.
https://forums.linuxmint.com/viewtopic.php?t=275495