not sure if this makes sense but, in addition to French for vocabulary and verb conjugation, a language that has helped me with Latin grammar is Japanese. I used to think declension was really intimidating, but it got a lot easier when I realized it's just Japanese participles if you attached them to the words: Accusative is like を, Nominative is like は,Dative is like に, and so on.
Obviously they aren't one-to-one comparisons, but it definitely got me over the initial hurdle of the newness of declensions
Always interesting to see how things connect
