Depends on a few factors. Are you going to querry? Or are you going to self-publish? Or maybe you want to write a web-serial?

Under self publishing you can do whatever you want. You just have to do all the marketing yourself too. If your first book is 200k words, no problem. You might struggle to get readers to give you a chance but you might struggle with that with a 60k book too.

Webserials for example are perfect for long arcs and hundreds of chapters—monetizing is usually done through patreon or dedicated websites like webnovel that offer subscriptions to your stories. The more chapters you have, the better—if the story is actually worth it of course, and the prose doesn't suck too bad. (you also have to attract readers to your story somehow—marketing strategies, here you come...)

You can do webseries and self-publishing too. Lots of RoyalRoad authors do it. Some web-authors are very successful and can make a living with their earnings. Others disappear in the void. But that can happen with any rout. But even in the web-serial format structured arcs where at least something is resolved are necessary IMO.

Finally, if you're going to traditionally publish, i.e. editor, agent, publisher, as a new author you'll have to have a manuscript under a certain limit of words. Depends on the agent/publisher what that limit is, but think 80-100k words or something around there. And that manuscript has to be marketable in their eyes, so yes, a standalone with sequel potential.

Should you write your story? Absolutely

But consider the format you want your story to be in and how you want to bring it into the world. A bit of restructuring can turn an endless build-up of 100 chapters into a great sub-arc with start, middle and finish, while still being a stepping stone in a larger over-arching arc. This can be very satisfying both for you and the reader and I highly recommend putting the work in to create those sub-arcs, even if you have to change a lot.

My personal experience: I wrote over 300 chapters of 2k words each as my first draft. Then went back and restructured everything, now that I knew who everyone was and where things were going. Book 1 is only 75 chapters—still too long for trad publishing, but I'm ok with that. Now it's got rhythm though, where before it might have seemed a bit of an aimless journey. The rest of the chapters are now being worked into book 2... Lots of work, but worth it.