To be fair to Simily, they are registered as "Simily, Inc.", a Delaware corporation. Here's a trademark filing they did a few days ago:

https://uspto.report/TM/97261130

identifying them as a Delaware corporation with a business address in Doylestown, PA.

So, at least that part of the story checks out.

However, their company address resolves to a mailbox service in a nondescript strip mall.

That's not sketchy in and of itself, but suggests to me that Simily is in very early days as a business. And, indeed, the USPTO filing lists February 2021 as the first day they used their logo, so it's about a year or so old. At most.

I'm guessing they aren't venture funded yet, so this begs the question how they are going to fund writer payouts. Very likely, the founders' pockets. Not sure how deep those pockets are, but it's very likely they won't be paying out enough for anyone to quit their day jobs yet.