Kylo Ren murdered Han Solo, Luke Skywalker, Snoke, and nearly took over the entire Galaxy in two films.
I’m pretty sure Luke won that battle, despite dying. Murdering Han wasn’t that impressive. Murdering Snoke was. And taking over the galaxy followed naturally, because Snoke had already taken it over. So really only one major accomplishment.
The greatest accomplishment ever honestly. Even Palpatine needed years and years of planning to execute his take over. Kylo pulled it off within one perfectly executed attack on the capital, followed by a coup of his own faction. All in the span of a week.