will my gcse results or a level subjects hinder my admission to a top uni?

i go to a pretty well known and respected grammar school, but due to (probably undiagnosed adhd) and other mental health issues (that were/are not diagnosed so cannot be recognised by the school) i performed quite poorly on my gcses. i got 9876665554. i hope to study some sort of social psychology or politics at university and am currently studying politics, english lit and psychology a level. i am also doing an epq which is psychology related. (i got my 9 and 8 in english language and lit, and my 7 in psychology - two marks off an 8). my hope is to achieve admission into UCL and study educational psychology there, but i have two worries. one is that my subject choices are not 'stem-related' enough for this course (and if not, it is not the choice for me as i am rather stem averse) and secondly that my gcse results will hinder my application. as a grammar school student, with parents with high expectations, i will be absolutely devastated if i dont get into a top university, at least a russel group or something else like bath which is still one of the best in the country. is there any way i can help my chances of getting into such a university or am i doomed from my gcse choices? additionally, with essay subjects being my strong suit, should i opt for a psychology course or go more in the direction of politics? thank you!