I'm sorry if my writing isn't up to your standards. Not intended as a tutorial, but I think the points are valid. With audio drop-outs and what seemed at times as a lack of control, this is how it's usually solved. While gfe is fine for single person streams, more complex arrangements require more complex systems/solutions. OBS is great for what it is, but maybe not as great as dedicated solutions.
You are writing it without examples. Which makes it confusing. Ideally you should have timestamps for parts of Tech Support challenge VOD to point out failures, what you think they are about and how to fix them. Also your title isn't really helping, or the starting paragraph. And since this is community forum, your start seems to be targeted to community, not as critique towards LMG.
LMG is hardly new to streaming. WAN Shows have been a thing for 8+ years. And they have gone much better with it. Even when they were doing it remotely. The key issue in WAN Shows for majority of time is that they don't have dedicated producer to take care of technical side of things. Like someone who could prepare everything, and monitor it while things are going. So the issues with intro scene and stuff like that fall down to does Linus remember how things are done and is there update to software which would break things.
With these dedicated streams they usually have someone in producers role (Anthony or Jake, maybe others now too). Reading chat, checking preview etc. With Tech Support Challenge they have added issue that they aren't fully in control of things. They are relying on internet connection of their contestants, those camera setups, software used by them to communicate and so on. Now, I haven't watched the latest, and since you have wall of text without context to quickly check, I can't comment on whether your critique is warranted or bit overboard.
I can say that since they probably can't have dedicated and private setup due to COVID restrictions (like contract with ISPs to make sure all connections are stable), the key issue is with what software they are using for video conferencing, and are they doing it on one call or multiple calls and then merging all to one. I doubt that any of the issues are because of hardware restrictions. I would guess network on either end, and software used for conferencing, are the main problems. Something which they would normally go around by doing local recording like with Scrapyard Wars on location.