I've been doing traditional kintsugi for about twelve years, a couple hundred successful repairs. Though when I started there was very little instruction or english-language resources available. It's become pretty popular for obvious reasons which is great for people getting into it now.
It remains probably the most difficult and frustrating skill I've ever learned. It's really hard to communicate just how meticulous, near-impossible some of the joins can be. There is a huge variety of technique and nuance to learn about different media and lacquer ratios for different kinds of joins & fills and it all needs to be done by intuition and experience.
And then the medium has no holding power until the curing process is well underway. So you need a lot of creativity to come up with a scaffolding system, pretty much completely unique to each project. Any problem after applying lacquer means hours of careful filing and rework, and more days or weeks of curing.
An edge-of-my-skill repair on a complete shatter takes about 100 hours spread out over 2-3 months. Even just an ideal three piece clean break is easily 8-10 hours and a handful of weeks.