Comparing a Yamaha s301bl to a rega elicit mk5 - a/b on some paradigm 800fs and they sound the exact same. Looking at the specs it makes sense - I don’t know why I’d ever use the full wattage of even the Yamaha without getting hearing damage and the THD being 0.019% vs 0.004% makes no functional difference. Are high end amps the new snake oil? What exactly are you getting for 10x the price here (besides the rega having less features and the rega brand name?)
Your Yamaha claims “ToP-ART (Total Purity Audio Reproduction Technology) combines a symmetrical circuit layout along with anti-resonance construction for high-quality sound with minimal distortion”. So you own snake oil, buy your own account. Thd isn’t the only thing that determines sound quality, sorry. But if you like your amp, enjoy it. Don’t claim it’s as good as every other amp in the world.