Does this job interview feel like a scam?

I recently had an interview at a startup and it feels suspicious to me. I would like to hear your perspective. I went through 3 stages of interviews. The first was with the HR, second product manager, then a take home assignment, and finally present to the CEO.

During my interview with the product manager, he shared his screen and opened their product’s dashboard. And asked for my feedback and how I’d improve it.

The take home assignment, including creating a landing page to advertise one of their services. Which feels like free work.

I received an email saying I stood out among other candidates and they liked my work ethics, but after the interview with the CEO, I followed up and they told me they decided to hire someone else.

I’m suspicious because I did read their reviews on glassdoor, most of them are negative. One person mentioned they think it’s a scam to get free work and they’re not going to hire someone. Do you think it could be true?