Work with SharePoint using C# code

I also googled a lot but I couldn't find any solution without using a username and password. You can use this solution https://github.com/pnp/pnpcore/tree/dev/samples/Demo.ASPNetCore It uses Azure Ad authentication. https://www.youtube.com/watch?v=2ZOnWp9mqY0&ab_channel=PiaSysTechBites also this one. But any solution doesn't give you what you want. I think it is necessary because you have to own some username for any SharePoint operations. Another solution is using powershell for some operations. If you have already some scripts you can easily run ps1 scripts on .net core.