Anyway, they updated that last issue with "Labels: Hotlist-DeveloperPain" only because that's different case and something to do with blacklist. Which I think might not be the case.
OK i found last bo reply for you:
"Webview and chrome do not have the same graphics pipeline. Chrome renders web content into a surface that it created and owns, and has complete control over scheduling GPU work. Webview renders web content into the surface that the rest of java views draws into; that surface is created and owned by android side, and webview only gets callbacks of when it should render, so webview does not have control over scheduling and does not get much feedback on the scheduling. Also webview exercises more gles APIs than chrome does for compositing, which possibly some drivers are slower at them. It's not clear what exactly is happening here, but symptom is swap is slow.
There isn't much apps can do to influence this. Chrome custom tabs / pwa is the way to go if you want to use chrome's rendering pipeline and still look like an app."
Chowdren runtime
That's seems to be some custom runtime/engine, what some guy makes and changes for each game separately and if you want it, you have to pay % share or his monthly working salary(which could be a lot for dev). That does not seems to be automated or what not.
You could possible buy game port to Unity much cheaper, ofc you then could/would also have to pay for port to Switch, but having port in Unity and not in some custom engine gives you much more options.