Exactly: you may not be able to fully understand the OS you're working with, but you can abstract it away and use it anyway. This isn't "technical debt", it's something you need to actually get your job done: without the OS, you simply would not be able to actually create the thing you're making.
Similarly, whatever you're building likely uses a microprocessor somewhere. You probably don't really understand how that works, and would not be able to build one from scratch. But without that CPU, you wouldn't be doing your job at all.
The phrase "standing on the shoulders of giants" comes to mind here.
"The Thirty Million Line Problem" by Casey Muratori might change your mind.
As an example everybody uses an OS to code. An OS is incredibly complex. Maybe one of the most complex piece of software. But it doesn't mean that you should care about it. With the proper and clean interface it will have an abstraction of this complexity to its user (in your company or not) and they will be able to continue to code and never have to care about it.
So of course an OS - or like OP said anything creating value - doesn't mean that it creates technical debt only because it's complex.