Do different speaker stands can really make a big sound improvement?

Much also depends on type of speakers you are using.   Found that Maggies blom with the added rigid support of Mye stands.  The Maggie community has embraced them and recommended as the most bang for the buck upgrade  you can acquire.

If you have a mid fi audio system (seems most folks here do) speaker stands won’t  make much difference. 
 

if you have an entry level or better high end audio system speaker stands can make significant difference. 

I could suggest a material for a Speaker Stand that will be beneficial material if the support structure to be produced from it is produced to be vert rigid structure.

Before considering different materials for a Speaker Support, the Support Plinth itself for the Speaker Stands when done correct, will bring substantial sonic improvements.

As DIYer I find multi tier plinths to be able to really allow the Speakers Cabinetry to get out of the way, in relation to influencing the end sound. 

Wasn’t Alan Shaw who said that as long as the stands are the proper height with the tweeter at the same level as the ear it doesn’t matter what stands you get? 

@audiopoint Your statement is factual and I have always found that the stands that is designed by the same manufacture to more beneficial is respect to sound quality, than any aftermarket stand. The mechanic's are often overlooked.  This review touches on this. https://parttimeaudiophile.com/2020/12/18/sonner-audio-legato-unum-loudspeaker-review/