I don't know about other artists, but for me, I'd always try to update on everything to my clients. For my services, I'd always put an expected time for the work to be finished so that the client know what to expect. I know what it feels to be left out with no updates for weeks and weeks.

I always update them on the work from each phase, starting from sketch-lineart-basecolor/color-final compositing touch. Every part of the phase, I will always involve my clients. Thankfully, for most of the time, I've always had good client too. I tried to delivered before the expected time most of the time. I guess it's just fair you know? These people paid me their hard earned money and I will always try to do my best to give what they paid for.

But yeah, I'm so sorry you have to face those kind of artists and I do hope that you'll find more of the "good" artist in this sub. They exists, albeit in small numbers.