removing an app which auto starts in Windows

I'd purchased a refurbished laptop from Amazon for A, and the seller rentopc had put a registration app to start whenever Windows logs in the user. Checked if there was anything in the startup folder, no

https://support.microsoft.com/en-us/windows/add-an-app-to-run-automatically-at-startup-in-windows-10-150da165-dcd9-7230-517b-cf3c295d89dd

Then, found it in Start -> Settings -> Apps -> Startup

https://support.microsoft.com/en-us/windows/change-which-apps-run-automatically-at-startup-in-windows-9115d841-735e-488d-e749-9ba301d441e6#ID0EBD=Windows_10