Tweaks work well when they are used as tweaks. They are literally the icing on the cake, and for that approach to work (the icing to do its job), you need a darn good cake for starters. Icing will not do any good to an inedible cake...
I am pretty sure no costly "tweaks" can beat by itself alone a systematic method to do the mechanical, electrical and acoustical control of the system working embeddings in the house/room/system at low cost...
I know it because i did it...
And nothing will replace anything; vibrations3resonance and high noise electrical floor and acoustic treatment and acoustic control are totally FOUR distinct problems to solve and the increase in S.Q. gained by solving each one of them separately cannot be compensated even by all the other together sonically ...
And even "tweaks" at low cost like the Schumann generators or the ionization of the room which i added with success in my own room may appear to be AT FIRST only " icing of the cake" but are in fact more than that: they add something completely unique to the sound quality, they are more than icing....I cannot eat my cake without them...
All that cost me peanuts, inspire yourself by LOOKING at costly tweaks, dont buy them, replicate them in your own way.... If i did it for many, then you can for some... I am not crafty at all...
I am a free thinker though....
😁😊