bhasvic student here- I don't do a language myself but I know people who do and be prepared for a lot of work, languages are probably the hardest A-Levels to do. I know you get extra speaking practice lessons, and most subjects have some form of help as well as the support plan if you're struggling.
its definitely a gamble for teachers, but its rare to get a truly horrific one and most them range from really good to ok.
there is definitely a lot of homework- the subject standard is 4.5 hours lesson time 4.5 hours homework per week but you'll have a bit more lesson time as you're doing French and Spanish
Hope this helps!