Unless they created a new user, and gave it sudo permission, this WILL, in fact, cause issues

@shanewjn : SSH into the server, then run the following, if you feel it is required to remove that user (which won’t hurt, if you ensure you have a different user in place):

sudo -i
adduser THE_NEW_USER_YOU_WANT_TO_MAKE
<fill out the form>

usermod -aG sudoers THE_NEW_USER_YOU_WANT_TO_MAKE

Next, from your local machine (if it has BASH commands, like if you are using GitBASH, you are running MacOS/Linux, or WSL) open a BASH/ZSH terminal and run the following:

ssh-copy-id THE_NEW_USER_YOU_WANT_TO_MAKE@YOUR_SERVER_IP_ADDRESS

It will ask for a password. Use the one you set in the adduser command.

Next, verify you can remote into the server with the new user:

ssh THE_NEW_USER_YOU_WANT_TO_MAKE@YOUR_SERVER_IP_ADDRESS

If it didn’t prompt for a password, you’re good to go.

Finally, for cleanup:

Set a password lock on the new user:

while logged in to the server as the new user, ensure you have sudo permissions:

sudo -i

If that works, your prompt will change to something that starts with root

Next, let’s remove the password on your account, as you should be set there.

passwd -l THE_NEW_USER_YOU_WANT_TO_MAKE

Next, open a new terminal, and SSH into your server as you just did:

ssh THE_NEW_USER_YOU_WANT_TO_MAKE@YOUR_SERVER_IP_ADDRESS

Now, let’s try to sudo up, and ensure there’s no issues with you having a locked password:

sudo -i

If it gives an error, stop here, and reply to me.
If it doesn’t give an error, the next step is fairly simple:

userdel centos

Best of luck!