I understand your confusion trying to Google this matter. The "trend IDE of the year" pulls the carpet below your feet, well, every year. They change names, ownerships, get discontinued, and everybody forgets about them. But you need to know the latest one in order to be the cool kid.
Just a few years ago, you were not trendy if you didn't use CooCox. Then it got discontinued without a warning, and you needed something else which I forgot already, now you need Atollic TrueStudio, soon it will be something else again.
So there is confusion, and all time you spend on these tools will be lost, you learn nothing. This being said, they don't require that much time, typically. The idea is, you get something running quickly, then concentrate on the actual code. Just don't take these tools too seriously, install something and see if it works. OTOH, if you do want to get serious, then I really suggest you invest some time, learn about the backend tool structure, and get the bare tools separately, and learn to use them directly. They are, and will remain, free software (open source), with decades of tradition, and no big surprises in sight. Everything you learn will be of great value for years and likely decades to come. I'm mostly talking about gcc and ld, and the relevant helper tools (binutils, like objdump). And, of course, make, although that isn't strictly necessary. They are not that difficult.
gdb and openocd are required for debugging and programming through the SWD interface, but debugging, again, is fully optional. For example, I work completely without, but my projects have become complex enough now that I absolutely need proper custom tooling and telemetry instead of one-size-fits-all beginner debug interface. My insistment of not using debuggers paid back very well since I was mentally wired to do it properly by myself from the start.