Duolingo has changed over time, especially for major languages like French and Spanish (and presumably English). Supposedly it’s going to try to incorporate some AI to enable some of the features you mention it lacks, but that’s very much experimental at this point. I’m not convinced it will work.
The two languages I study most in Duolingo are French and Spanish.
For French I have the advantage of having studied it for a very long time and had the opportunity to actually speak to other humans in that language. I retained my ability to read French, but my spoken and listening skills deteriorated from lack of use. Duolingo helped me refresh those and I’m now listening to some news every day in French, although, alas, my opportunity to speak it is still largely non-existent at this point.
Spanish I hear out in the community. I am now picking up some words and phrases when I hear it, and occasionally it’s come in handy when a *abuela * with poor to non-existent English skills comes through my checkout line. But then, I’m hearing real people having real conversations, not a computer or phrase book regurgitating sentences.
Since my spouse passed away I’ve been hanging out with my local Jews and have been hearing Hebrew in bits and pieces. I’ve been dabbling with that as well, and hearing it spoken, again, has helped although learning a new “alphabet” (technically, it’s an abjad) is daunting, as is reading right-to-left. Pretty sure Duolingo will not make me fluent in Hebrew, or even functional.
I think Duolingo works best to either refresh language you learned in the past or in conjunction with more/expanded learning.