I changed admin name and did not change home directory. Mac not working properly anymore.

Change the name of your macOS user account and home folder

Excerpt " You can change the name of your user account only while logged in to a different account, which must be an administrator account. If your Mac isn't set up with another administrator account, you must first add an administrator account in Users & Groups settings: "

Sorry but you have to Start Over

Try this...

Open System Preferences>Users & Groups, unlock the lock, click on the little plus icon, make a new admin account, log out & into the new account.

Does it work in the new account?

You tried it in Safe Mode???

Try it in Single User Mode...

On startup hold Command + S keys until it starts in Single User boot .