I've been using the Teensy 3.2 in my experimental arcade game Line Wobbler (mostly just using the wave generator in various ways) and simply using a capacitor and the DAC pin to a small amplifier board, as recommended here.

I've been looking how to do this on a Teensy 4, and since there's no DAC on it, I've been looking for alternatives. So far, the simplest seems to be using two PWM pins, but that's seems to be more parts and less resolution. Are there other work-arounds? I'm also happy to spend 1-2 USD on a little board. Perhaps an I2S amplifier board? FWIW, I'm driving a 3W (mono) speaker.