I saw the news about WebView2 and it is disappointing - it would have been great to have WebView2 running on Windows, macOS and Linux. It'd have been a consistent approach which makes it as easy as possible to port between platforms with a broad feature set. Unfortunately Microsoft kept us waiting for a few years promising future support before then retracting that, so we had worked on a long-term plan that isn't going to work out any more.
I have been considering our options for the long term. I would prefer to ultimately move away from NW.js and Electron. The whole node component of these frameworks is both redundant and a major complication to supporting things like Steamworks. The node APIs are really complicated and difficult to maintain - I'm not sure what the situation with Electron is, but for NW.js every native addon has to be recompiled for every new version, which makes maintenance way more painful than it needs to be. Maybe things would be a bit better with Electron, but we'd still have node sitting in between native code and web code which makes everything harder. This blog outlines how the Windows WebView2 exporter is our ideal architecture: node is not involved at all - it's basically a webview that talks directly to our own simple extension system that involves posting JSON messages, and means we can write our own native integration with things like Steamworks, and they are forwards compatible so require minimal on-going maintenance. It's much much nicer than having to deal with node and our hope was to roll that out to macOS and Linux too.
On macOS we already have the WKWebView export option, and it's possible we could add our extension system for that export option too. I was hoping to use WebView2 as it uses the Chromium browser engine and has better features for things like file system access. We could probably set that up and work around the missing features, although it will be more difficult.
These days I think Linux support is actually more important, as it's what we need for Steam Deck support. NW.js does the job there for now. But we could perhaps look in to using something like WebkitGTK to essentially build a custom in-house wrapper for Linux, and then integrate our extension system for things like Steamworks support. This is a significant project and I don't have much Linux development experience so I'd have to get up to speed on that, but I think that's our most likely future direction, as a minimal in-house wrapper like we have with Windows WebView2 is actually much easier to customise and maintain. This is all long-term stuff though - it may be months or perhaps a year or two before anything appears on this front. For the time being we'll get by with NW.js.