rename homefolder

Luis is correct. trying that is just asking for trouble. i don't recommend changing it. but if you must change it, please read Change the name of your macOS user account and home folder - Apple Support. if you don't do it correctly, you are risking your account and ALL of the data contained within it. and, of course, make a backup before hand if you don't have one already.

Why would you mess with your home folder? Changing the username or the home folder is asking for trouble. You are risking data loss. What for?

How come your home folder does not match your your username to begin with?

Although it can be done, it's a tricky dangerous process. First step, ensure you have a backup. I would propose the following for most people versus the SysAdmin type process.

Undo the name change you already made then create a new administrator account, move your data to a new folder on /Users/Shared than login as the new admin account and move the data back to the new accounts home folder. Only delete the bad account once you are sure absolutely everything is working and accessible. It is very important to ensure the new account has administrative privileges so make sure you check the box when creating the new user to allow the user to administer this computer. You can royally shoot yourself in the foot if you manage to remove all administrators from a new T2 equipped Intel Mac or the new M1 Macs. They have hardware encryption from the factory and you might not be able to boot. Make sure you test boot and go for a week or so using and trying everything before you remove the old "apple" created account.

They did NOT rename your home folder. They created a new account for their testing. This account had none of your personal files, did it?

The correct way forward is NOT to rename anything.

Do you have a Time Machine backup? Use Migration Assistant to bring back your account from the backup.

No backup, or just your files copied to an external drive?

Create a new account with the desired name, login to that account and copy the files.

When all is done, you can delete that "apple" account. [Though one should always keep a second admin account as a safety measure, but that is another matter]

Time Machine is an easy way to backup your data. You can set it and forget it and, when you need to recover a file or the whole contents of your drive, it is there for you.

All you need is a sufficiently large external drive (it should have at least two or three times the size of the data you have; for example, if your internal drive is 250GB and all your stuff fits in, a 1TB backup drive is perfectly adequate). It does not need to be a fast drive.

When the Time Machine drive is connected, your mac will periodically backup. It is incremental, so only files that change will be copied, and several versions of the files will be kept, as space permits.

You can "navigate back in time" and recover a file that you deleted or that you inadvertently changed. This has saved me a few times.

And when it comes time to get a new mac, or to reformat the drive, you can migrate from the Time Machine backup and pick up where you left off. So, say you get a new M1 mac today. Start it, attach your backup drive, and when asked, select to migrate your account and boom... new mac, with all your mail, photos, music exactly as they were on the old one.

Really with Time Machine there is no excuse not to have a backup.