I’ve heard from amp builders and others how important transformer size and quality are for delivering speaker performance. No one’s mentioned it yet, and I am not finding a definitive source on the web, but these two are both decent.
https://www.psaudio.com/askpaulvideo/tube-amps-and-output-transformers/
and,
https://wallofsound.ca/audioreviews/amplification/what-difference-does-an-output-transformer-make/
My QS mono blocks have great transformers; they control the bass on my speakers extremely well, and I have compared them with some very good solid state.
What this discussion seems to indicate, then, is that there are a number of commensurately important factors necessary to creating good sound. Finding "synergy" between speakers and amps is not magic; it comes down to understanding the various factors on amplifier and speaker sides, and matching them. Then, listening.