So, if symptoms include laptop fan thinks it's a jet engine, Start menu refusing to fully populate, Search not responding, and a lot of apps just not launching at all (or taking several minutes to do so), a quick look at the Services tab in Task Manager for WinHttpAutoProxySvc, followed by go to details and End task on the corresponding svchost.exe might just do the trick. You can ignore the big scary warning about this restarting the system: that's a lie.
For a slightly more permanent fix, paste the following into a .reg file and merge it into your Registry:
Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\WinHttpAutoProxySvc]
"Start"=dword:00000004
This will disable the service (which Microsoft has made impossible to do via regular GUI or CLI tooling), and after a reboot, you should be able to, like, use your PC for a while. Keep an eye open for rogue Windows Updates, though, as Microsoft really, really wants to re-enable this service using those. (Apparently, WinHttpAutoProxySvc does all kinds of important stuff, including address assignment for non-native IPv6 setups, none of which I care about, but before blindly following 'just disable this thing' advice from the Internet, just think for a while before rolling it out to your entire fleet).Playing whack-a-mole with WinHttpAutoProxySvc has been oddly satisfying so far: one of these days I might actually grab a debugger to see what's going on here (because, yes, also after updating to Windows 11 22H2, which re-enabled the service, I had the same-old symptoms within days -- I admire the writer of this article for getting a fix for their problem that worked!)