You're scrolling down the aisles of scribblehub or RR and see an interesting title. You do what any sapien would and add it to the "plan to read" list. But how long does it marinate before you pick it up?
For me, I usually wait for 30+ chapters so I can binge. Depending on how I liked it from those first 30 will decide if I let it marinate for 100 more.
When I have time (when I'm not writing), I'll mostly read finished, and published, novels or light novels. However I haven't had much of that lately.
Most of my "free" time is dedicated to my own writing, and occasionally (when I need a break) reading the stuff I'm working on reviews and critiques for.
I tend to prefer to read finished works that are at the very least up to the par for formal publishing (be it self-publishing or professionally produced and published) because nothing beats the feel of a real book in your hands.
Around 20.000 words is usually what I wait for.
That's what, 8-12 chapters?
To me that is usually when the exposition is mostly done and all important characters are introduced to the reader.
To address your question, 20,000 words will roughly land you in a wide variety of different chapter counts.
For example, most light novels average around 2500 / chapter which does come out to 8 chapters, so your typical Light Novel will hit the 20k mark at, or around, the 8th - 9th chapter. This, however is simply one literary approach.
Another for example, is what most published novels aim for and usually end up around. ~20+ Chapters @ ~5,000-6,000 words per chapter; for an average total length landing around ~100,000 - ~120,000 words per novel. Some can go even higher than that. This narrative structure puts the 20k mark squarely within the first four chapters. (Shameless Plug: It's also the narrative structure that I'm aiming for with my own releases here on Scribblehub as well, and I can personally attest that Duskfall Chapter 2 on its own landed at 10k total, and Aestelle Nocte Chapter 4, which is as of yet unreleased, will probably end up in the same range. These chapters are released in smaller parts though, to make reading easier on the platform).
On the other end of the extreme, I've also seen some stories up here on Scribblehub that barely land in the 1k - 1.5k / chapter range as well, and that would bring your target's chapter count up to around 14-20 chapters, give or take. This, however, tends to be more of a trend with amateur-level web-novels than any form of published media. (Not that there is anything wrong with this narrative structure, I'm simply remarking on my own observations).
Hope this helps with the clarity. (And yes, having the word-count goal is actually more reasonable in my opinion than a chapter count because it ensures at least a consistent narrative depth before you take the time to invest in a story.)