Source: https://www.reddit.com/r/CrackWatch/comments/fli390/um_guys_...
[ Link about Doom Eternal launched with and without malware - 0day news. ;-) ]
Many of these systems are just continuations of anti cracking schemes that go back to the 80s, littering the checks for piracy throughout the software in otherwise unrelated function calls and causing them to be tripped in situations that aren't necessarily the initial bring up.
Modern software like this is more akin to malware than license checks. Many of them will try to detect containerization, virtualization, and tools which might be used to monitor their memory to defeat the checks. Most run with root privileges and will install their own extra malware to try and detect tampering outside of the actual binaries. This is very similar to the detection that are done to try and defeat anti malware scanners. You can get around this by using hardware memory editing devices which are sometimes used to cheat in games without any ability to be detected.