More maths is always useful for prospective scientists, in any field, so it seems a natural choice to do it. Being a scientist isn't like being a doctor, where you might be more focused on providing care to patients than doing research, designing experiments, analysing data etc, and so maths less useful or essential. This latter stuff is
what it means to be a scientist. Of course, you can do a science degree without becoming a scientist, but that begs the question of why not do another degree? If you don't want to learn the language of modern science (yes,
even biology), that is to say maths, why do you want to do science? It's like wanting to do a history degree without using primary sources. Consider your motivations in wanting to pursue a science course - what are your long term goals? Does it make sense to pursue a science course for these?
While as above if you aren't motivated to do well in it you likely won't, but given you'll be dropping a subject after a year anyway you're really in a no-lose situation. The subject you might drop may as well be maths so at least you have had some exposure to post-GCSE mathematics before you start your degree. If you take it, do well, and find the A-level content more engaging than the GCSE content (which is what I found; I didn't particularly like GCSE Maths and did decently in it but was never particularly motivated for it, but found the A-level content much more interesting both in of itself and in it's applications) you can continue, if not, drop it.
Given your situation, I think you would be doing yourself a disservice to not at least attempt it. Additionally neither RS nor Psychology give you any more options when it comes to applying to degrees than you have now, and don't add any skills you aren't already developing in your other A-level options (in e.g. written communication etc, via Biology and Geography). There are some natural sciences courses, and many other STEM courses beyond that, that require A-level Maths (or at least some post-GCSE Maths) however, and you at least give yourself the possibility of having this wider range of options available to you by taking it.
This is I think a case where it's worth taking a chance, since you always have your first three subjects to fall back on if you don't like maths