Did a zoom call with the CEO, everything went ok. He sent me a coding test. The coding test takes about 4/5 hours, not difficult.
CEO told me to send in the test ASAP. I told him it was a busy period for me, so it would take me a couple of days, and then he said its ok.
I did it in 2 days, even though I had to work late a t night. After doing it, I asked him via email how to submit it. He did not answer me for 3 more days, and then casually answered "just send me the zip.". After another couple of days, he sent me a rejection message, no specific reason.
What I feel has happened is that, being the company a startup, they try to hire on the cheap, so they had other candidates at the final stage of the interview process, but they wanted to do "window shopping" to see what they could have bought.
I am very happy it went that way, because it showed me how they treat their developers.