Problem with Administrator account

It's a bit long story that I got over it initially, but it seems I still have something hiding away.

A. It started after I disabled the Defender's real time scanning, to install a sizeable program.
I restarted Windows at the end of the installation and went to check the Defender's status.
It was still disabled (should have reverted after the reboot). Even worse, I couldn't enable it again!! And I was still showing as an admin.
I created another user (same name I was using with a number 2 added to it). Also an administrator.
Restarted logged in a the new user, forgot the password 2-3 times and locked into a loop. Rebooting, I only had the new user as a choice.
I made a bootable USB, got to the main disk through DOS and copied the text file where I keep my password, over to the USB.
After I read the password, I started the main computer and the silly thing came alive as usual. It seems that the bad password lock has a timeout...

Other than a question on how could the administrator rights misbehave, the first part is done with.

Now I have my normal admin (kanen), the new admin (kanen2) I never used, and the PC's admin group with those 2 accounts in it.

B. I tried to install another big application but it would crash soon as I run its main program.
So I started uninstalling and reinstalling it in various ways:
Making the installer's compatibility to run as admin. crashed the same way. Same with running the installer in an admin command prompt.
Last I tried the administrator prompt from PowerRun v1.8.
And the program started!!

Except, the profile folder it created, wasn't under C:\Users\kanen\AppData\Roaming\ (like it was supposed to be), but instead under C:\Windows\System32\config\systemprofile\AppData\Roaming

And that makes it useless since the program can't update its preferences, and even MsEdge can't write its own control folder into that path.
Copying/pasting whatever was in there to where it was supposed to go and trying to change the program's preferences, doesn't work. (Folder must be empty or contain valid data is the response when I reassign that folder).

So why the normal admin installation doesn't work, and PowerRun works but doesn't use the current user's environment?
And is there a way to make sure my normal admin is real and not a look-alike? Switch to the built-in admin, and flip-flop the normal account's admin maybe?

Sorry if I didn't phrase the above properly and I hope it's understandable.

Cheers.