TShock fails to run, "You must install .NET to run this application." even if Mono JIT compiler version 6.8.0.105 is successfully installed.

[creeloper27]

• TShock version: 5.1.3 (latest at the time of writing)

Reproduction steps

1. install Debian 11 (Bullseye) on a x64 system
2. run sudo apt install mono-complete
3. cd to a dedicated folder (in my case: /home/user/servers-and-services/terraria-server/)
4. get the latest TShock version (TShock-5.1.3-for-Terraria-1.4.4.9-linux-x64-Release.zip) and unzip it (I used wget https://github.com/Pryaxis/TShock/releases/download/v5.1.3/TShock-5.1.3-for-Terraria-1.4.4.9-linux-x64-Release.zip and 7z x TShock*)
5. run chmod u+x TShock.Server
6. run ./TShock.Server
7. TShock fails to run

running sudo apt install mono-complete successfully:

>sudo apt install mono-complete
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
The following NEW packages will be installed:
mono-complete
0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
Need to get 36.9 kB of archives.
After this operation, 77.8 kB of additional disk space will be used.
Get:1 http://deb.debian.org/debian bullseye/main amd64 mono-complete amd64 6.8.0.105+dfsg-3.2 [36.9 kB]
Fetched 36.9 kB in 0s (416 kB/s)
Selecting previously unselected package mono-complete. 
(Reading database ... 368484 files and directories currently installed.)
Preparing to unpack .../mono-complete_6.8.0.105+dfsg-3.2_amd64.deb ...
Unpacking mono-complete (6.8.0.105+dfsg-3.2) ...
Setting up mono-complete (6.8.0.105+dfsg-3.2) ...
Scanning processes...
Scanning processor microcode...
Scanning linux images...

Running kernel seems to be up-to-date.

The processor microcode seems to be up-to-date.

No services need to be restarted.

No containers need to be restarted.

No user sessions are running outdated binaries.

running ./TShock.Server unsuccessfully:

>./TShock.Server
You must install .NET to run this application.

App: /home/user/servers-and-services/terraria-server/TShock.Server 
Architecture: x64
App host version: 6.0.11 
.NET location: Not found 

Learn about runtime installation:
https://aka.ms/dotnet/app-launch-failed

Download the .NET runtime: 
https://aka.ms/dotnet-core-applaunch?missing_runtime=true&arch=x64&rid=debian.11-x64&apphost_version=6.0.11

other notes:

• I have tried using mono on other applications and it seems to work, here is also the output of mono --version

  >mono --version               
  Mono JIT compiler version 6.8.0.105 (Debian 6.8.0.105+dfsg-3.2 Tue Jun 29 21:01:01 UTC 2021)
  Copyright (C) 2002-2014 Novell, Inc, Xamarin Inc and Contributors. www.mono-project.com
      TLS:           __thread
      SIGSEGV:       altstack
      Notifications: epoll
      Architecture:  amd64
      Disabled:      none
      Misc:          softdebug 
      Interpreter:   yes
      LLVM:          supported, not enabled.
      Suspend:       hybrid
      GC:            sgen (concurrent by default)

• I also tried to install mono using the tutorial in the docs here but unfortunately there is no mono repository for Debian Bullseye (11) at the moment

[PotatoCider]

Mono isn't required at all. You would need to install the .NET6 runtime