its rlly good for basics !! esp if you dont know the alphabet too well and just need to learn vocab. i think u should consult like a speaker of the lang for things like fluidity of a sentence but tbh duolingo is pretty good
It teaches you hangul for most of the lessons and words as well so it's a good choice but if you need any help, I can help you learn! My dad is half Korean so I've needed to use korean a lot.
I tried it for a little bit but I didn't really learn much. Mostly because I didn't do the ¨15 minutes a day¨ like it tells you to but idk-
Ik it has helped a lot of people though so you might as well give it a shot since ik its different for every person