After roughly a month and nearly two-dozen exchanges with support, I was offered the option to escalate the case to engineering. By that time, however, I had already upgraded to Ryzen AI HX 370. Furthermore, I ended up returning the 7840u and repurposed the 7640u in a new chassis, passing it down to a family member.
So, I thanked support and encouraged them to escalate to engineering, but excused myself out of the loop because at this point Framework have all the info they need to reliably reproduce the issue in a lab environment, albeit, they might have to procure some hardware to do so. Given BIOS updates breaking docks or other hardware isn’t that rare, it’d be the right thing to do.
At any rate, I hope Framework will invest more resources into making sure their products not only work by themselves but also with, at least, a small set of well-supported hardware (such as docking stations, external displays, etc.). This is a tall order, but the BIOS situation definitely needs a ton of improvement.