it is always a battle between performance you can get away with and ease of development
in case of server development java and c# offer a comfortable compromise between the two
and with .net 6 on the way with features like AOT the gab between it and c++ is getting closer even if it isn't by that much
a few years back c# was right next to java or worst in that benchmark
so i would recommend c# but i might be biased here and i don't have much experience with the other languages