Conrad johson versus lamm

No clipping but with high volume i hear aggressive acute

It is also possible that the Tweeters get overloaded, then they start to glare (a kind of your aggressive acute). It isn't so uncommon, Tweeters aren't so robust than other chassis, that's one reason why some Manufacturers replace them with electrostatic (or similar) panels (see Verity Audio, Wilson Alexandria ...) when high volume is demanded.
Regular tweeters work very well until they reach their technical limit and then it is done, from one second to the next. You don't see them so often, because their price is higher for the manufacturer compared to conventional chassis (most are mass market units, a little bit modified for each manufacturer) :-)

Dynaudios are more or less know to be a money grave for amplifiers. No matter what you do, the stronger amp will be always better, unfortunately good sound and high power is nearly impossible. Most high powered amps sound dead and boring. Quite a task to find a good one. Good luck.
It is much easier to look for a speaker which makes audiophile life more enjoyable :-)