Spawn chunks are kept simple by purpose and the datapack does not use functions.
The thing is: the server does not do much (no players online in MC). So I wonder how the server can be laggy.
Update:
Deleting and recreating the account in the launcher solved the problem.
I've just migrated one account from Mojang to Microsoft and get this ominous error "Something went wrong in the login process" repeatedly.
My system is Kubuntu 20.04 and I have gnome-keyring installed.
System warnings are:
gnome-keyring-daemon: asked to register item /org/freedesktop/secrets/collection/Default_5fkeyring/6, but it's already registered
[email protected]: asked to register item /org/freedesktop/secrets/collection/Default_5fkeyring/6, but it's already registered
I haven't upgraded to 24w03a or later yet but the problem hasn't occured for several weeks now. Maybe it's fixed now somehow.