I think WebView2 doesn't currently support these window positioning methods out of the box. I filed an issue about it a while back.
Can I ask why you need this though? It seems a weird thing to do. If you're trying to set a specific window size, it should default to the viewport size of your project.
Thanks for taking a look Ashley, appreciated.
I dont think it's weird at all, window scale is a very normal option to have for desktop games (i dont do web games). Especially if you do pixelart, your game is made in a much lower resolution and then scaled up. Letting the player then select the window scale in options (or go fullscreen) is seen as hygiene factor for many. Celeste is a good example of this.
I use this JS method because Construct does not provide a native way to scale the window. Would love if that would change moving forward but until then this is the best way to do it from what I've gathered.