I’m a massive fan of the YAMAHA THR5 and it’s become my go to amp for playing and recording guitar at home. I’m using it plugged into my 2016 MacBook with Logic Pro or GarageBand.
First off you’ll need to install the drivers on your Mac (this is for Big Sur), head here. Then once downloaded, head into the folder that you downloaded and double click on the .PKG file and follow the install instructions. If prompted to enable extensions you’ll need to head into System Preferences, then General, then at the bottom you should see a prompt for Yamaha, click to allow then restart your Mac.
Once you have restarted then you just need to change the sound input settings in the system preferences. To do this you need to load system preferences, then click sound, then for OUTPUT select THR5.
You can now use this within Garageband or Logic Pro.