The Dynaudio didn't sound bright to me at all so don't know what the other commenter is referring too.
The Gold 100G actually has pretty good balance of tone just with some thinness that I heard during demo with Samara Joy's music and she doesn't have a thin vocal presentation. Like the heft and body was a bit lean. Outside of that, overall balance was acceptable.
Also your 706 S3 don't lose their brightness. You got used to it cos they're annoyingly brittle sounding whilst also lacking snap and pop to drum hits, brass instruments. It's like they sound muffled and harsh at the same time.
Any speaker you get will sound less contrasty to begin with and you may not like that compared to your 706 S3's more coloured presentation @spoonman16510