L7 Informatics, Inc Applications Engineer interview questions

I received about nearly ten e-mails recruiting me to interview for L7 over several months and I finally responded. So I have the first call, with a VP, very enthusiastic, they even said "offer could be next week". Then come their "take-home" challenges (3). Two were standard very basic easy and took little time. But the first was literally to create a full blown web application where user could upload file, this certain known odd feature of certain datasets was to be assessed, and a visual report presented describing the data distribution contrasted with this weird law. They even wanted it docker containerized and essentially fully ready to go with built-in deployment in an isolated Docker container. I spent about ten hours on that, thinking, they must think I'm perfect for the role - why else did they reach out over, and over, and over, again? When it came to the actual video interview with the VP and two director level ppl, they seemed very pre-occupied and unenthusiastic and I got no responses or interest in the work I had done for the challenges nor any feedback whatsoever. Huge waste of both our times, mainly mine