Basic networking is a Roon issue because this is a product that, at its Core, is expected to utilize the network as the backplane of various supported devices. Guides and tweaks for specific issues and vendors need to be published on a continuous basis. But, notice something, I said “basic”. That’s really key.
I read the support thread and, honestly, I think Roon did complete the basic troubleshooting here. There is an issue with Google Wifi mesh and your set-up related to the way Roon/Remote does discovery and streaming. But, this is well beyond “basic”. Now, it would be nice if Roon saw this to completion so they could publish a doc to prevent others from tripping over the same issue. However, maybe they don’t think the combination of SonicTransporter across Google Wifi mesh has enough of a user base to devote the resources to getting to that point. Additionally, they may just not be all that interested in diving deep into mesh wireless.
What you really need is someone who can troubleshoot your network against a specific application. That industry doesn’t exactly exist sadly but I continue to see a growing need. I recently worked with a Hifi/HT shop that is starting to do this kind of work but they are seeing mixed results and success as they would rather just replace the network with known good hardware that works well with the software they are installing (it’s often cheaper for the customer as well compared to paying per hour for troubleshooting). You can find people on gig sites (like Fiverr) who will work with you remotely to troubleshoot as well. I’m not sure how you find a qualified person in this situation but the list of people claiming to know Wifi grows every day.
Anyway, I’ll get to my point. You posted this in the “Roon Labs LLC” group so I’m defending Roon as a company and where I would expect them to put forward resources (people) to troubleshoot Wifi issues. I’d expect this level of support would be minimal. This is not a Roon software issue. They have implemented their discovery and streaming in a way that puts a very heavy tax on the network (probably the highest I’ve seen in a “consumer” product) and that requires a whole different level of “good” when it comes to how well your network is performing. It also means that just because your other devices work fine you should not expect Roon to work just as fine. What you really need is an investment in a consultant who can work on your specific set-up who both understands Google Wifi Mesh and Roon to identify why issues are popping up. I wouldn’t expect that consultant to be Roon (although they could use the pay by hour support method here as a new revenue stream). That consultant might be Google as your software works when eliminating the Mesh. Or, and probably, it’s going to be a third party in an industry that is just starting to identify itself. Enterprises already have these people on staff. Geek Squad and the others are certainly not at this level of knowledge yet. If you have a local hifi store you may ask them if they’ve got into the networking business yet. I also know this is becoming big business for the home automation industry.
If I was to troubleshoot this… just based on my background…
I would start with network packet captures at strategic locations within your set-up. Just based on your description it appears that data from Core to endpoints is fine but data from devices back to Core is being “modeled” and then choked down to nothing. During playback there is a lot of data being passed around the network, in both directions, and it sounds to me that either the Mesh network cannot handle it and effectively crashes or the Mesh network is literally just dropping packets in an attempt to get the Wifi devices to back off (there are a bunch of ways to do this within the standards). A packet capture at multiple places would show this. The unanswered question of this theory is if there is a setting in the Mesh network that can cure this or it is simply that the Mesh backhaul is running out of steam and causing things to collapse. Obviously two very different solutions based upon the root issue. I use this summary of how I’d troubleshoot this to illustrate the fact that the next steps in your troubleshooting are no longer “basic”. Roon narrowed the issue down to an issue with the Mesh network but identifying a solution to that feels very out of scope for Roon; at least to me.