Players can see my commands

Hello!

I created a server. And the players on it can see when I do /give or /gamemode creative even though I am the only one with op. Can someone please tell me how I can stop them from seeing those commands?

In the chat. I am the only one with access to the console.

Update - apparently he can see it because he is OP. But I never gave him OP. I deop-ed him from console and it said Nothing Changed. The player is not an operator. He can kill me, set his own gamemode to creative, give me blindness effect, give himself command blocks, etc. But he is a good friend of mine. He told me he isn't using a hacked client and I believe him. How can he do all this???

Another update - Apparently he is not op, since he can't use command blocks, /ban or /op but he can kick me, set my gamemode to something else and do all of the things I mentioned above. He said it's because of the permission plugin. I have LuckPerms on the server but the only permissions I gave everyone are:
ultimatehomes.home

• ultimatehomes.home
• ultimatehomes.sethome
• ultimatehomes.delhome
• ultimatehomes.sethome.unlimited
• ultimatehomes.warmup.bypass

Everyone on the server has these permissions and nothing else so why can he do all this?

Yeah probably, I realized that too. But how can I fix it? I don't want him to see every command I make.

Ok I will try that but LP just made everything easier. I don't want to give all the players on my server op, I just want to give them permissions so they can use the ultimatehomes plugin. And I don't know how to give permissions without LuckPerms, I am not good at this sort of stuff.