What is Microsoft Edge Webview 2 service?

You can get rid of it but some Windows features will get broken as Start menu

It is a built-in service of Windows 11 now.

No worries. It is safe but unfortunately you can't disable it currently.

I also distrust Windows, it is generally cited as a not-so-secure system, an example hese temporary files.

I also distrust Windows, it is generally cited as a not-so-secure system, an example being these temporary files.

Basically, Microsoft Edge WebView2 is a component that allows developers to embed web content in their applications.

When you're seeing it's multiple instances, this is because they're rendering different part of web content on browser/apps/widgets etc. on your system.