+1 When the Sith was introduced I was not vibing with them much, but to remove them would fuck with a lot development made specifically for them. I think those suggesting a restructuring would be fine. Why not make them some sort of "Cultists" similar to Mother Talzin and the night sisters? Like in old republic there was a branch of the Sith who were like the Revanites and they still followed Dark side practices but instead worshiped Revan. I'm sure if we delve deeper into lore we could find some sort of darkside cultist tribe that would make for better immersion.
EDIT: I decided to go through and search for a few and here's what I found that may make for better possibilities!
https://starwars.fandom.com/wiki/Prophets_of_the_Dark_Side
https://starwars.fandom.com/wiki/Disciples_of_Ragnos
https://starwars.fandom.com/wiki/Church_of_the_Dark_Side
https://starwars.fandom.com/wiki/Cult_of_Exar_Kun
Side note; we could also make our own "Cult" and have it based around the teachings of former Dark Lords of the Sith from the Old Republic! I think that would be pretty cool. Possible options like Followers of Xendor, Acolytes of Naga Sadow, etc. Some random stuff like that.