If it's the same issue I had, what's causing this is DX12. For some reason after a certain update, launching the game with DX12 enabled takes way longer than it should. If you let it sit unresponsive for a while, in my case like 2-5 mins, eventually it loads and then loads with no issues afterwards. If you can't get it to load after waiting you can go into game settings in the battle.net app and tick "Additional command line arguments". Add "-d3d11" and it will force the game to launch with DX11. Should work then as a temp measure.
I just updated to the new AMD drivers and also having this same issue like in November. Those old solutions didn't work for me then, but my old one did: I left it on the black/white (it's been changing) for 5 minutes or however long it takes and it went. Don't know why that works, but whatever I guess. It's just annoying.
Clearly the AMD driver is the issue. Very frustrating