Yeah, doing a complete reinstall was my very last step. I have a sluggish DSL connection, so downloading the game took almost 24 hours.
Some people seem to be having success following the suggestion here: Infinite updating loop - #32 by Exxaxion-drakkari
You might try that first.
The weird thing for me was that everything was working perfectly fine for hours, days, and weeks, then I paused playing for a couple hours and came back only to find I couldn’t stay connected and, when I tried a scan and repair, I got that infinite loop.
I’m in no way an expert on these matters, heh. I do wonder if some kind of security feature was implemented by someone in the chain—Blizzard, my ISP, auto updates to modem or router, or even auto updates to my PC’s Windows Defender—that started causing this disconnection problem and, later, the scan and repair problem. But after all the steps I mentioned above, I was finally able to play again, just a few hours ago.