A contract is not something that you will automatically get just because you've reached the 50k words requirement. There are other requirements that you need to fulfill.
As I already said in my previous post, you also need to prove that you have a consistent release rate and quality. A consistent release rate is something that can be obtained simply by updating daily or weekly, as long as it's steady, but a consistent quality depends on their evaluation of your novel. E.g. Do they think your novel is good enough for their users base? Is there an audience for it? Does it have the marketability factor? And so on and so forth.
So, unfortunately, I can't answer your question. The period in which writers here have to wait before they get offered a contract varies; there's no fixed answer. Also, please keep in mind that there's always the possibility that your story may not get contracted at all.
If you haven't joined the inkstone discord server, I suggest that you do. You can find a content editor there that will be able to answer all of your questions. Content editors are the people who scout around for good new stories to offer a contract to.