You can also run Diablo III from the command line if you want to bypass the Battle.Net app entirely. There are a couple of options like -launch and maybe -w or -window to run it in windowed mode. That would definitively exclude the Battle.Net app as a cause.
I haven’t had a Diablo III crash in a long time. Only issue I’ve had in years was a few weeks ago when I got kicked from a server and my account got rolled back about 3-5 paragon.
For what it’s worth, I recall Razer drivers were an ongoing issue with D3. That could be worth checking.
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