Need a project to build

Not sure, I've built dacs, headphone amps, and regular amps.

Maybe a solid-state headphone amp. Or, I was thinking of some linear power supplies for dac / raspberry pi that puts out 5v.

I had to send my smsl dac back to china to get repaired (the display stopped working on it) hopefully I get it back.
 
I didnt see _speakers_ on that list - maybe you need to do something to get the cans off the head for some of your listening pleasure?

I agree, it typically isnt much of a circuit. No multi-node circuit, when you get to use DSP -