What kind of anti-debugging technique doesn’t allow attaching with usermode debugger?

I’m currently in the process of learning different techniques malware use to prevent debugging, and I came across an issue I can’t seem to really understand. This piece of malware that I am currently trying to figure out and debug uses some kind of anti-debugging technique that doesn’t allow me to attach a debugger in the first place.
I have tried using things such as Scylla-hide, I’ve also tried manually going in and hooking common anti-debugging API calls to see what is going on, but no luck so far. I also tried with WinDbg hoping it would give me some error message I can go off of, and it gave me this:
WinDbg output when trying to debug program

So this got me thinking that it was doing something to prevent a thread being started and that is what is causing any debugger from being able to attach. I also tried injecting a DLL with the typical LoadLibrary CreateRemoteThreadEx technique and seems it doesn’t allow me to create a thread that way either. I’ve looked at as much as possible on anti-debugging and can’t seem to find an answer to this. Any nudge in the right direction would be greatly appreciated.

I’m hoping to be able to circumvent this in user-mode, as I’m trying to understand what exactly it is doing to stop me from debugging rather than simply bypassing it. This is my first time asking a question so sorry if anything was hard to understand.

Source: StackOverflow