commands from mods do not work on the core mohist 1.16.5

"Doesn't work" is not a good description of your problem.

What did you do?

What did you expect to happen?

What actually happened?

Quote from 151gamemode1chit

Code

when I, for example, highlight two worldedit dots, an inscription appears - this means that the mod is correct and works, but when I write // set 1, it says "Unkown comand. Use / help", and // set is not displayed in / help, etc. .d.

Then you don't have permissions to execute the command. You have to give yourself OP.

You need the mods on the server and the client.