everything sounded great until the upgrade

Without knowing, it may in fact be that "X" sucks is your problem... impossible absent data.

But keeping it simple - you liked amp A, you dislike amp B.  What's the question?

Amp synergy is not usually a huge deal unless either the speakers or amp or both are way out on some extreme - which in most cases means flawed.

You will also hear "its break in".  Uh, not in extreme. As a professional designer do you know how many new and cold things i hear? Sure they sound better warm. But they don't sound bad cold....unless they are in fact bad.

Why did you buy something without hearing it first?  All the pointless bickering here aside, that's what matters - where the eardrums meet the air

I am afraid to upgrade, i dont need it, i dont want it, but i am also afraid to do it...

I already have a good synergy, for reason of S.Q./ price ratio , i cannot upgrade my 50 bucks top of the line Mission speakers nor my low cost dac marvel, then the amplifier?

I own 2 Sansui amplifier because i loved it so much...

Upgrade may be useless when you are in acoustic love.....

I am afraid to upgrade like someone afraid to lose his wife or trade her....

In spite of what most think , some minimal quality threshold being passed over by the gear, the electronical design change is less impactful on listening test than acoustic and psycho-acoustic change in the speakers/room relation...

A difference is not always or  so often than people think, a great acoustical improvement...

This is the information lacking in all audio threads...

Check it...

wine improves all systems.

wine improves all systems.

With the empty bottle you can use a straw for the neck and experimenting with a primitive Helmholtz resonators...

I begin my first one like this...  😁😊

If you liked the sound of your modest system.....that bis all that counts.