> I eventually ended up investing in building my own "detached" office in the back yard

This is the thing I want most in work life right now. I have a separate semi-dedicated office room but it splits time as the guest room and has basically no auditory separation the rest of the house including a 3yo and a 1yo.

Edit: OP would you be willing to share pictures of your space? I love seeing how people set up separate office spaces.