Comment by Animats

> 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.