Issue 1:
JRiver uses the default web browser, not Chrome, for rendering the web page. I say this knowing that 99.97% of all Android users are likely just using what Google gives them. I am not normal and actually use Firefox, Chrome and Edge at times and switch often. Edge renders the page but has oddness. Firefox seems OK for now. And yes, I realize that every browser in the Play Store has to use Google's rendering engine. That doesn't change the fact that, for some things like this, there are odd things that don't look right in those browsers.
Your fix will likely be "just use Chrome." My response will be, who are you to tell me how to use my phone? I don't tell you to use Internet Explorer on your Windows 10 PC, don't tell me what browser to use on my phone please.
My current workaround is to just copy the URL and open the browser I want to use. I do not know if there is a way per app to require a specific app be spawned, in this case, Chrome, when you try to open JRiver. If there is, I would say might be a good idea to configure that.
Issue 2:
I have seen it asked several times but not answered. Will JRiver use the default audio path on Android devices or can it use the advanced audio options afforded to devices like LG G6? Or if I plug in a USB-C DAC, can it use that? My understanding is that app have to be specifically coded to allow this capability and not all apps offer it. If JRiver can do today or will be done in the future to offer this, then I would say it could be close to the 1:1 player we have on Windows (eventually). If it doesn't or won't, then I would say the name should be changed as the pedigree will be lost with this new product. My opinion, of course.
Sorry if it sounds like I am bitching. I am not. I can work around the issue I experienced but not sure I should have to.