So block lag basically. Wouldn't suggest Hamachi myself, cause there are much more better ways like port forwarding or ngrok. The block lag is cause either ur pc sucks and cpu is weak or it can be ur internet aswell or even a mod hogging all of the cpu. Can u fill this "form" so i can help u better.
What MC version and how many mods are u using:
What is ur CPU:
How much ram do u have and how much have u allocated to ur server.
How great is ur internet(speedtest.net):