Audio gear test: deciding how deep to go

I’m new here, and as I posted in the DIY page I started with the cheapest system possible (Pi zero, $5 USB DAC, $30 amp, but did have big 25yr old speakers). This setup sounds fine to me, but I wonder what I’m missing.

I recently found this tool. It’s pretty great - a blind sound test of different styles and compressions. On my computer with regular headphones I could tell the difference but not by a huge amount. Sometimes I was even wrong about which were the higher quality files (test yourself! be honest)

I just thought I’d post a link in case anyone else is going through this journey. The sound files are downloadable, so you can drop them onto your Volumio as well.

This test only goes to 16/44.1 - does anyone have a similar test that goes even further?