Will an Amp change improve my system ?

I have the 30,2 40th anniversary (almost the same as the XD) and matched it with a Pass Labs XA25. It is a match made in heaven. Don't know about your room size but, it is plenty for mine of 20x12. If you want some info about the combo, please check Herb Reichert's review in Stereophile Mar 2018. The interconnect is a RCA Cardas Rev1 and a good match with the Pass. I have tried different stands and highly recommend the Ton Trager. More expensive but  it makes Shaw's cabinets sing because of their resonance configuration. Keep us posted about your choice for a new amp.

The S300 is a fine amp for the price, but for me the Pass was much better sounding...don't know your speakers though...some love Benchmark, but very many do not...

First of all how big is your room?…after you answer I will give you my honest opinion if you can handle the truth…let me know …

I had the PRIMALUNA EVO 400 preamp and amp…not impressed 

To answer your question, no, an amp will not significantly improve (or hurt) a system regardless of what the sufferers of expectation bias will tell you.

your list includes warm tube amps and analytic dry amps, complete opposites, do you know which sound you like?