Is there a way we could have lessons that help us practice verb endings?
But just the verb endings, to help us memorize them? Maybe it could be like the timed bonus rounds!
If I may suggest a little workaround:
Find some site about Italian grammar (I see you're learning Italian). Open the topic on conjugations. You'll most surely find a few dozens of popular verbs there.
Take a good old paper notebook and write conjugations of these verbs.
This will only take one or two hour sessions, and you'll remember the endings quite well. After that, return to Duolingo practice—it won't let you forget the conjugations and will drill them well with random verbs and forms.
I did that for French and it turned out very useful. Don't be afraid to use external resources.