I need to retrieve my password to get administrator access back in macOS High Sierra [duplicate]

I have a MacBook Pro that I have forgotten my administrator password to. I believe I last logged into it in 2018, so I am still using macOS High Sierra because I can't upgrade without being in the Admin setting.

I have still been able to work some on my Mac because my son helped me set up another user account for myself back then.

I have tried with Apple Assistance in the past when I still had my 3 year coverage Service Plan upon purchase of my Mac, but we could not get in then either.

I need to add a DAW to my computer for making music, as well as, connect my other music producing and recording equipment for which I bought my Mac for.

If you want create a new Administrator on your Mac, you need boot in Recovery Mode. (cmd+r at boot) . If Filevault is activated, from Disk Utility, you unlock/mount the System Volume giving the password. (right click on the system volume). You quit disk utility, then on top menu you select Utilities/Terminal I suppose the System Volume name is "Macintosh HD", the command is :

rm /Volumes/"Macintosh HD"/var/db/.AppleSetupDone

If no error message you reboot the Mac and then you will be invited to create a new administrator.

Then you can modify and repair your initial User admin account.