There are many documentaries that explain the work culture in SKorea. It is expected to do more than what is required, not to mention that the culture of entertainment is overfocused in the fans, that's why they apologized for not taking care of themselves even if they are putting their health at risk. I imagine the comic industry is the same.
I can assume that drawing a single chapter is a ton of work (and hours). If you spend all your time sitting at a desk in front of computer, you start having issues with your back, eyes, wrists, and so on.
Their deadlines are tight so they often don't even get a day off during the week, so they take hiatuses every now and then.
Honestly, one chapter per weekend is insanely fast pace for that amount of artwork
It's because they're under such tight deadlines that they have to get such high quality rendered art + plus the actual plot storytelling given every week not to mention on apps like webtoon or others that might have advanced chapters you can pay for they work even more to do those, so that's more than 1 ch every week they have to produce with no weekend holidays or hardly any at least.
That means they stay in the same position staring at a screen constantly drawing for we talking 12+ hrs, hardly eating or sleeping or taking a break to meet said deadlines which is extremely detrimental to their health. Not to mention it's probably even worse because doubtfully they're going to doctors when they notice something slightly wrong healthwise and only go when they're at their worst case scenario hence y the hospitalisation and so they have to take a break. A good portion develop carpal syndrome,basically losing feelings in their hands and numbness, which is y recovery can take even longer and if their health gets rlly bad they have to quit the series all together.
If U ever read end of season qna's a good portion of artists/authors talk about theyre insane schedules and things they do to keep up and unfortunately it's the norm in the industry to literally work urself to death, the companies are pretty predatory and so this treatment is now seen as the norm industry wise.

Can someone explain why so many artists have health issue? It's been quite a while since I started to read BL/Yuri and I am shocked every time by how many artists take a hiatus. Is there a reason? (I hope I don't sound judgmental, I am just genuinely curious)