What is the best way for asp.net core to make a cross-platform program?

These days I want to make a cross-platform program in the windows&linux system for using a socket to control a device.

With .Net it seems there are two ways: one is asp.net core, the other is Xamarin.

I have never learned Xamarin before so I am about to use asp.net to solve this.

As we know, we should wrap the page into a program no matter in Windows or Linux.

There are several ways: Electron/Webwindow.

In these articles:

https://blog.stevensanderson.com/2019/11/18/2019-11-18-webwindow-a-cross-platform-webview-for-dotnet-core/

Electron cost so much performance.

Webwindow still has some bugs and has not updated for a long time. And also, it is only a personal experimental project and no one knows whether it will be support in the future. 

I don't know what should I do now. Or I can only learn the Xamarin.

.Net 5 is coming soon while there is no information about which framework it will support for cross-platform.

I can hardly wait for the .Net5. Please give me a suggestion. Thank you.