Using YubiKey --> Install the required packages: --> macOS --> gnupg2 not necessary if you are using gpg-suite (which you should be)

In the "Using the Yubikey --> Install required packages --> MacOS (https://github.com/drduh/YubiKey-Guide?tab=readme-ov-file#using-yubikey), it says to run:

sudo port install gnupg2 pcsc-tools

However, if you have gpg-suite installed on your mac, installing gnupg2 from homebrew may cause gpg problems or errors in GPG-suite's version of gnupg. I have talked to the GPG-Suite developer, and they said if you have gpg-suite installed, you should not have any alternate versions of gnupg, which would be gnupg2 from homebrew. I'm not sure about pscs-tools either, but have to do some more research into it.

In summery, it should be noted, that if you have GPG-Suite installed on your mac, you DO NOT WANT TO INSTALL gnupg2 because it will could conflict with gpg-suite, and is not properly tested on mac, whereas GPG-Suite is highly tested on MacOS. Check this post for notes by the developers: https://gpgtools.tenderapp.com/discussions/problems/138945-gpg-keychain-exported-pgp-key-is-diffferent-than-imported-pgp-key-what-gives

So instead, use

sudo port install pcsc-tools

without gnupg2,

or...

sudo port install pcsc-tools & brew install gpg-suite

to also install gpg-suite version of gnupg2 (recommended)