(PC) Unplayable desync issues since the last bout of maintenance

So, I’ve been having the occasional rubber banding issue since I picked up D2R on PC last September, but since the last server maintenance day, I’ve been getting atrocious desync to the point of unplayability. I can desync from Battlenet servers for 4, 5 seconds at a time, and have gotten kicked outright a few times. Maybe 20% of the time, the game will work mostly fine with only some rubber banding, but usually it’s so bad it might as well be a slideshow.

Are there known causes/fixes for desync and rubber banding that I should be aware of?

For info: I’m still running Windows 10 at the moment; all my network diagnostics come out clean and I have no connection issues whatsoever with anything else at all; the game is smooth as butter with every graphics option on Ultra in solo play; and the issue persists even if I switch regions when booting the game.

I’ve tried all the standard tech supporty stuff: rebooted the computer, rebooted the modem, fully uninstalled then reinstalled the game, to no avail.