The PC App Store malware is hard to remove.
1
The best first option is to check if you have a system restore point dated prior to PC App Store being installed on your PC that you can go back to.
Click your Start Button, then just type rstrui and press Enter to open System Restore.
2
Then, download the Microsoft Safety Scanner and run a full scan with that.
https://learn.microsoft.com/en-us/defender-endpoint/safety-scanner-download
When that scan completes, download the free version of Malwarebytes and run a full scan with that.