Update: So yeah...about that tidbit I mentioned regarding reverting my default browser back to Chrome from Firefox Quantum. Either it's the weirdest coincidence ever, or it legitimately resolved the issue. Been online in the game for 2 hours now with no issues at all. During all the mess I was enduring, I would've had at least 3-4 disconnects in that time frame at a minimum.

Beats all I've ever seen.