I do english lit (OCR), history (OCR), politics (edexcel) and french (AQA) rn and I'm still alive! As others have said, you don't need 4 to get into the best uni in the world but my school made us start with 4 so I just had to get on with it. At my sixth form we don't have 'free periods' we have 'study periods' (depressing ik) where we do independent study in the library. I have 1 study period a day 4 days a week and on the other day where I don't have one, we have enrichment where we do an activity and I've done things from debating to film review to crochet to colour by numbers.
I think there's really interesting bits in politics that can overlap with law, such as the topic on issues surrounding the constitution, and we even end up looking at law cases as examples to use in essays in my politics lessons. The best thing i found to do well in my subjects is to stay consistent and try to create systems for each subject. I found it best to create my own revision guide made up of my class notes & the textbook for history and politics, whereas for english, i focused on having a large bank of quotes and key info to memorise on an app called Remnote (but you can also use notion). Revision for french was completely different because I got to do something apart from just learning facts all day, so I ended up enjoying moments where i got to do speaking practice or just ANYTHING but write huge essays all day.
I may be biased but I think you should do a language, just for a bit of variety if you do end up doing 4. To be honest, all the subjects you are considering have some level of overlap and will all be great for a law degree!