During the opening of the game, Minecraft simply freezes and Windows says it's Not Responding.
Here's the log file:
[15:03:00] [Client thread/INFO]: Setting user: grizzlybear1024
[15:03:02] [Client thread/INFO]: LWJGL Version: 3.1.6 build 14
[15:03:04] [Client thread/INFO]: Reloading ResourceManager: Default, oldclassicminecraft.zip
[15:03:05] [Sound Library Loader/INFO]: Starting up SoundSystem...
[15:03:05] [Thread-2/INFO]: Initializing No Sound
[15:03:05] [Thread-2/INFO]: (Silent Mode)
[15:03:06] [Thread-2/INFO]: OpenAL initialized.
[15:03:06] [Sound Library Loader/INFO]: Preloading sound minecraft:sounds/ambient/underwater/underwater_ambience.ogg
[15:03:06] [Sound Library Loader/INFO]: Sound engine started
[15:03:11] [Client thread/INFO]: Created: 1024x512 textures-atlas
[15:03:13] [Client thread/INFO]: Narrator library for x64 successfully loaded
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I did use discord, closing it fixed the issue. What's causing that?! That's bizarre!
This is a known issue: MC-124460. It may possibly be caused by Discord's "Overlay" feature (not 100% sure on that though).

Maybe, just maybe, check the sound engine. I have a hunch that's what it is
Are you using Discord? If so, does disabling it fix your issue?