So I made myself a sort of client-side phone callback system: https://youcallme.io.
It starts a conference call with you and the client service line letting you enter the DTMF tones. Then you hang up while it awaits a human to be discovered. Have actually been playing with a couple of different human detection approaches from call screening to a bit of ML. Once spotted calls you back to sign up with the conference.
So far has actually conserved me 45 minutes with Questrade and 2 hours with CRA (Canada’s IRS).