pls help!!!! psychology a level for medicine?

i want to do medecine, preferably at a London uni such as icl, icl, kings college, queen Mary or something like that. all my predicted grades for gases are 8/9

I want to take biology chemistry and psychology for my a levels, but I've heard lots of people say that psychology is a 'soft' or 'easy' subject and that if I want to apply for medicine in a Russell group uni, it will give me a disadvantage. I've heard SO many people tell me that maths would be better, and even though maths is one of my strongest subjects, I'm not that interested in it compared to psychology. I would do maths if I really needed to, its just that I'd so much rather do psychology. ik that Cambridge and Oxford are the only unis that want 3 sciences, but I'm not planning to go there

will taking a psychology a level instead of maths be a disadvantage for the unis that I'm looking at going to?

(also please don't suggest that I do 4 a levels, I honestly cba and would rather focus on 3 and get the best grades possible)