I could do the publish+start+attach only from VSCode. However, it's not such a big pain, normal coding can be done in VS. VSCode is open next to it and if I need to debug on RPI, I switch to VScode and start the debug session.

This is my launch.json config in VSCode:

    {
        "name": "RPI 192.168.0.xx",
        "type": "coreclr",
        "request": "launch",
        "preLaunchTask": "publish",    <--- this contains the pscp copy part
        "program": "~/.dotnet/dotnet",
        "args": [
            "/testapp/app.dll"
        ],
        "cwd": "/testapp/",
        "stopAtEntry": true,
        "console": "internalConsole",
        "pipeTransport": {
            "pipeCwd": "${workspaceFolder}",
            "pipeProgram": "c:\\Program Files\\PuTTY\\plink.exe",
            "pipeArgs": [
                "-pw",
                "<your_password>",  <--- for local tests ok
                "[email protected]"
            ],
            "debuggerPath": "~/vsdbg/vsdbg"
        }