That whole thing about speed just ends up being a cycle. I've been in the translating scene for too long to know that some readers will never really be happy with how fast you're translating something so personally, I just go at my own pace lol. But on the other hand, depending on what type of translator you are (quality vs quantity), that's the type of readers you get. I personally get a lot of readers that care more about quality since that's what I prioritize. I sometimes do get the "When's the next chapter?" comments but that's understandable, and a lot of them are pretty nice about it.
Exactly. I've actually done the same thing for a few stories (mostly CN) where I tried calculating how long it'll take before it finishes, and it just takes too long. Which is why I tend to choose those with less chapters.
I think tl;dr people lean more towards quantity (somewhat readable at least if TLer wants to keep their reader fanbase along with decent reviews) when it's hella long, and quality when it's shorter.