I have the same isue like you with my server 1.21.3.01 I have 48 core 768gb ram but 100% cpu on all core when someone go in nether. with any cpu core (4,8 16 or all core) and options in config file
client-side-chunk-generation-enabled true or false cause same issue with my server i'v 3 server with same nether bug on linux centos
BDS-3266
I have the same isue like you with my server 1.21.3.01
I have 48 core 768gb ram but 100% cpu on all core when someone go in nether. with any cpu core (4,8 16 or all core) and options in config file
client-side-chunk-generation-enabled true or false cause same issue with my server i'v 3 server with same nether bug on linux centos