Hi 
Aternos, I would like to suggest a plugin that removes spaces from playernames. I find this plugin, 
NameSpaceRemover, very help as when opping people in-game, as it just replaces the space with an underscore ("_"). It is also currently kept updated, and here is the link:
https://poggit.pmmp.io/p/NameSpaceRemover 
P.S.; Please except this great plugin!!!!
