What do you think about KDP Amazon?

I wanna ask you guys if kdp still profitable and good idea to start or you're advising to start another business and what do you think about competition in this particular business ?

Depends of your interests really. If you are passionate enough about it, you can make work it out for you. If you do it only for money, then find out about your passion first.

every single business/nich is profitable, it's only depends on you

Used to have several profitable KDP accounts, and all got banned over time. Amazon introduces new rules and if even 1 book doesn't meet the new standard you get banned.

It's much better to have full control over how you make money, than rely on platforms who can remove you at the drop of a hat.

I do have a few books on Draft2Digital and make a few sales here and there. (Passive beer money, not that I drink).

Its doable though high competition, look at the Youtube, full of KDP tutorials, people are crazy, moms, fathers, side hustlers, dogs/cats, geeze.

If you are really good at design, I guess you can always try it or Redbubble etc, and stay out of the crowd in one day, keep patience, consistently produce new designs.