Duolingo is fine, you just have to be aware of its limitations. Getting the trophy isn’t going to represent the finish line of most peoples language goals, but it’s a decent start.
Duolingo is a great start. It takes a lot of effort to get those trophies. I think they are getting better with AI/ML to interactively tutor you as well. Personally, if you can afford in-person or virtual practice with a native speaker twice a week (about $30-40/week via iTalki), I think that is when you make the jump from dabbling in a language to becoming a serious student.
I’ve found it best to learn the basics through something like duolingo, and then follow that in with a tutor once there’s a base of vocabulary to go off of.
Obviously a tutor is great, but the cost and time of a tutor isn’t worth it at the beginning stages for me personally.