You don't need any real educational resources to get good at soldering. Any random primer will do. It's genuinely a simple task that doesn't require a lot of explanation or have a lot of tricks.

What gets you good at soldering is just practice. Solder a lot. A fun and easy way to do this is to pick up those cheap ($5 or less) electronic solder-it-yourself kits and do a bunch of them. Include ones that contain small surface mount parts.

You can also practice desoldering on them, or pick up broken electronics and desolder parts from those.

> managed to desolder and resolder a stick but the controller doesn't turn on anymore.

There's a chance to practice repair (which is a completely different topic from soldering)! Odds are very high the problem is that you've made an unwanted solder bridge or you have a cold solder joint.

> repair (which is a completely different topic from soldering)

Yes. There's repair, rework, build and debugging.

Repair is mostly diagnosis, followed by cleaning and repair of mechanical damage. ICs themselves don't fail much. That's what the original poster is doing.

Rework is mostly careful desoldering followed by new component installation. That's when hot-air rework stations are needed, if you have to replace ICs. This is a "use the right tool for the job" task, where you have little metal heat gun air guides for each IC shape. (I have a bag of those things.)

Building, where you start with a blank board and a supply of components, all with a known-to-work design, is just small scale manufacturing. It takes some skill and training, but the process is simple and repetitive. It's automated in production shops.

Debugging of new board designs requires not just soldering tools but the test equipment to test the thing and an understanding of how it works. This is what electrical engineers and technicians do.

I find watching videos of other people soldering is almost as good as practicing myself.

Or both.

Seconding the practice-kit thing, but for the dead DS4 specifically: before you go hunting the joint you reworked, check whether you lifted a pad or cooked a via near the stick. On those boards the stick pins sit right next to thin traces and a hot iron parked too long will pull the pad up with the pin. Easiest check is continuity from each stick pin to wherever the trace lands, and check 3.3V is present with it plugged in - if the rail is gone you probably bridged something, not broken the stick.

Other thing that got me: no-clean flux residue plus a cheap iron with a bad ground can look like a dead board when it's just leakage. Clean it with IPA and a brush and retest before desoldering anything else.