I once had a company give me an assignment that sounded very much like what you are describing. They said I should allocate 10h at once to implement a real-life task that they had and that their developers "already solved".

At that point I only wrote a handful messages with their recruiter and hadn't even spoken to a human there. I didn't even know anything about the team, my potential boss or the project at that time.

I didn't even answer back, just ghosted them. I'm not going to spend multiple hundreds of Euros of my time just for some assignent to maybe qualify for an interview.