Each project is throwing ControllerConnectionException on startup - exception

Question

Ok, I don't rly know where to start, but let's do this.
So for two weeks I had my last working day where everything was working fine in VS 2019 (16.11.4). Today I wanted to start a project, and i got the following error message:
Unfortunately, a process used by VS has encountered an unrecoverable error.
Stack Trace:
Microsoft.ServiceHub.Client.ControllerConnectionException : Controller terminated before accepting connections. Exit code: -1073741674.
at async Microsoft.ServiceHub.Client.HubControllerClient.StartAsync(<Unknown Parameters>)
at async Microsoft.ServiceHub.Client.HubClient.LaunchOrFindControllerAsync(<Unknown Parameters>)
at async Microsoft.ServiceHub.Client.HubClient.GetLocationServiceAsync(<Unknown Parameters>)
at async Microsoft.ServiceHub.Utility.Shared.ServiceHubRetry.ExecuteAsync[TReturnType](<Unknown Parameters>)
at async Microsoft.ServiceHub.Utility.Shared.ServiceHubRetry.ExecuteAsync[TReturnType](<Unknown Parameters>)
at async Microsoft.ServiceHub.Client.HubClient.GetThisAsRemoteServiceBrokerAsync(<Unknown Parameters>)
at async Microsoft.ServiceHub.Client.HubClient.<Reset>b__54_0(<Unknown Parameters>)
at async Microsoft.VisualStudio.Threading.AsyncLazy`1.<>c__DisplayClass13_0.<GetValueAsync>b__0[T](<Unknown Parameters>)
at async Microsoft.ServiceHub.Client.HubClient.GetPipeAsync(<Unknown Parameters>)
at async Microsoft.ServiceHub.Client.HubClient.RequestServiceAsync(<Unknown Parameters>)
at async Microsoft.CodeAnalysis.Remote.ServiceHubRemoteHostClient.RequestServiceAsync(<Unknown Parameters>)
at Microsoft.VisualStudio.Telemetry.WindowsErrorReporting.WatsonReport.GetClrWatsonExceptionInfo(Exception exceptionObject)
Followed by another error:
There was an error activating the remote language server. Plese select Help > Send Feedback > Report a problem.
These errors also appear, when I create a new project. The only way I can start VS19 without errors is, when I click "Continue without code" in the popup.
So I tried to repair or modify VS. When I want to repair it, it failed. The popup which is prepairing the repair info is shutting down with no error message.
I didn't find that much information in the internet, especially with the error code.
Furthermore I detected, that I cannot install or uninstall VS19. Plus, I cannot install VS22, because it is aborting again after the "preparing the VS installer". Again no error is poping up.
A sample log:
[2cf4:0001][2021-12-15T17:45:47] Saving the current locale (de-DE) to user.json.
[2cf4:0001][2021-12-15T17:45:47] Setting the telemetry services
[2cf4:0004][2021-12-15T17:45:47] Creating a new telemetry service.
[2cf4:0001][2021-12-15T17:45:47] Visual Studio Installer Version: 3.0.4496
[2cf4:0001][2021-12-15T17:45:47] Raw Command line: "C:\Program Files (x86)\Microsoft Visual Studio\Installer\setup.exe"
[2cf4:0001][2021-12-15T17:45:47] Using registry value of (1) to theme installer.
[2cf4:0001][2021-12-15T17:45:47] Getting singleton lock. Mutex name: DevdivInstallerUI
[2cf4:0004][2021-12-15T17:45:47] Telemetry session ID: ...
[2cf4:0001][2021-12-15T17:45:47] Getting singleton lock succeed.
[2cf4:0006][2021-12-15T17:45:47] Creating new ExperimentationService
[2cf4:0006][2021-12-15T17:45:47] Telemetry property VS.ABExp.Flights : lazytoolboxinit;fwlargebuffer;refactoring;spmoretempsbtn1;asloff;keybindgoldbarext;asynccsproj;vsfricheditor;completionapi;tn-vsmacnps-7;toggleblockcomment;tasmigddvs;multitenanttasmigration_002;vsfdevcom2;lsprmsgvol;debugger-init-asynccf;vswnewinstaller;links_carousel_tfl;azure_links_tf
**[2cf4:0003][2021-12-15T17:45:47] An abnormal shutdown was detected from the previous telemetry session.**
[2cf4:0004][2021-12-15T17:45:47] Telemetry property vs.willow.source : WPF
[2cf4:0004][2021-12-15T17:45:47] Telemetry property vs.willow.locale : de-DE
[2cf4:0004][2021-12-15T17:45:47] Telemetry property vs.willow.installerversion : 3.0.4496.34889
[2cf4:0004][2021-12-15T17:45:47] Telemetry property vs.willow.startmethod : direct
[2cf4:0004][2021-12-15T17:45:47] Telemetry property vs.willow.activityid : ...
[2cf4:0004][2021-12-15T17:45:47] Telemetry property vs.willow.campaign : 70
[2cf4:0004][2021-12-15T17:45:47] Telemetry property vs.willow.passive : False
[2cf4:0004][2021-12-15T17:45:47] Telemetry property vs.willow.quiet : False
[2cf4:0004][2021-12-15T17:45:47] Telemetry property vs.willow.processtype : ui
[2cf4:0001][2021-12-15T17:45:47] Monitor center position: 960, 585
[2cf4:0001][2021-12-15T17:45:47] Showing the window.
I didn't really know what Telemetry was for. Can this cause any issues due to fireall/network problems, that I cannot install, repair, uninstall VS?
With sfc /scannow I got following lines:
2021-12-16 16:25:52, Info CSI 00000293 [SR] Cannot repair member file [l:15]'mscorlib.ni.dll' of NetFx4-mscorlib_ni, version 4.0.15805.350, arch amd64, versionScope neutral, pkt {l:8 b:b03f5f7f11d50a3a} in the store, hash mismatch
2021-12-16 16:25:52, Info CSI 00000294 [SR] This component was referenced by [l:78]'Package_3_for_KB5004331~31bf3856ad364e35~amd64~~10.0.4400.1.5004331-51_neutral'
2021-12-16 16:25:52, Info CSI 00000295 Hashes for file member [l:15]'mscorlib.ni.dll' do not match.
2021-12-16 16:25:52, Info CSI 00000297 [SR] Could not reproject corrupted file \??\C:\Windows\Microsoft.NET\Framework64\v4.0.30319\NativeImages\\mscorlib.ni.dll; source file in store is also corrupted
Does this have any connection to my general problem?
Maybe(!) a very similar problem, this guy was facing:
https://developercommunity.visualstudio.com/t/visual-studio-installer-vs2019-keep-crashing-sudde/711824
So... (further) things I tried:
Installed .NET Frameworks again
Tried the reapair tools for VS and .NET
Tried to repair VS19, but I cant
Run sfc scannow
Run chkdsk scan
Several reboots, restarting VS, ...