I’m sorry to hear of your connectivity frustrations. I’ve been there and I know how frustrating it can be. I used to be confident Wyze was the problem too, so I can relate. I couldn’t understand why some of my friends were telling me they had 0 problems with Wyze at all, and there I was having so many. I desperately tried so many things to figure out what the difference was.
I’m not necessarily saying the following is the problem, but, just so you know, when you are streaming with Bluestacks using the Wyze app, your video streams are most likely staying 100% local on your router and never using your internet bandwidth at all other than a split second at the very start for “authentication” with the Wyze server confirming that your computer is allowed to connect directly to the Wyze cams locally over the local router. After that it’s all local, no video even leaves your house.
When you use the “webview” through a browser, that is apparently through an entirely different method and IS actually using your internet to connect the camera through an Amazon server and then relay it back to your computer again. So the Webview is actually using both your upload and your download bandwidth, while Bluestacks does not. Since you asked, that is one reason why there is a difference. Now, I am not necessarily that is the primary issue. I don’t know much about your particular situation. There are nearly countless things that could be involved in your frustrating experience…I’m just saying that your bandwidth speeds are irrelevant to bluestacks and the app when you are on the same network as the cameras. It’s not using your internet bandwidth to live stream the camera in that case. It works totally differently.
I will point out though, that you mentioned you are using Comcast Xfinity…and while I won’t definitively say that is the problem, I will say that when I had Comcast XFinity, my Smart home experience was an utter nightmare of problems that were related to so many things. I detailed a list of things I found to help improve my experience here if you’re interested in seeing if any of those things could be making a difference in your experience too:
While I do sometimes also have to refresh the webview, and not all cameras always start on it because the webview isn’t totally perfect, I don’t have all the other loading and freezing and lagging problems you are reporting on the phone live view. Mine work really well. This leads me to believe that some or most of your frustrations are likely related to having Comcast XFinity just as I had all those problems when I had them, and as soon as I switched off them to a good solid Fiber internet with a different ISP, and Router, all those problems magically went away for me. I know not everyone has those options since Comcast sometimes has a monopoly over certain areas, but sometimes you can improve the situation through things like changing the DNS, ditching the Comcast gateway for a better router, etc. (even their best routers/gateways were always terrible in comparison to alternatives…they will tell you their router/gateway is great and charge a ton for it, but I always found even their good gateways were terrible overall).
I had Comcast at multiple locations and they were all horrible. It has become my default to believe they are the primary problem with any connectivity frustration because in my experience it’s always turned out to be the case…it just sucks that sometimes there aren’t really many better options. 
Hopefully my other linked post above can give you some ideas of things that might help a little, or someone else might have some ideas too. But once I got rid of Comcast, my experience has been exponentially better with almost no connectivity issues anymore, even though I have 40 cams using cam plus, uploading nearly constantly, and over 300 total Wyze devices, all without connectivity problems. So I have become fairly convinced that most connectivity problems are not exactly Wyze’s fault since it’s possible to have near perfect general connectivity with Wyze.
As for the Webview, I do sometimes have some cameras that don’t start up right away for some reason (though most of them usually do), so hopefully they can make some improvements to that method since they are using a different protocol than the app normally uses.
I hope you can find something to help your situation for the rest of it though, and I will also continue to advocate for improvements to the webview. As you said, some of the webview frustrations are likely not due to your internet, but due to the webview still needing some improvements.
How many cams do you have, and how many are you trying to stream at the same time?