How valuable is a 4th A-Level for competitive unis?

Hello! First, some context: I am a Year 12 student currently taking Maths, Psychology, Politics, and Comp Sci. My goal is to get into a psychology course at a top university (ideally either Oxford or UCL, but I'm not dead set on anywhere yet). My grades have been good so far, but the workload between my end-of-year exams and my AQA Comp Sci NEA project has been pretty painful for a while now. In short, what I'm doing at the moment doesn't feel sustainable.

So, my question is: how impressive would a 4th A-Level look on my application to a competitive university? I know universities only ever make offers based on 3 grades, so is it actually counter-productive to take a 4th, knowing it will probably make it harder for me to get the grades I need in my other 3? The way I see it, I have three options. I can either keep doing what I'm doing and get 4 good A-Levels (probably at the cost of my mental health lol), completely drop one and get 3 good A-Levels, or cut back on something like the Comp Sci NEA and get a not-as-great grade in that subject but have more time to devote to my other 3. What I choose to do depends on how it will affect my university applications; does anybody have any advice about finding a compromise between workload and grades?