EPQ is compulsory regardless (big sigh). I started sixth form doing 4 a levels too, but it was pretty tough to keep up so I dropped to 3. Just as a curiosity, what subjects are you wanting to do?
I started sixth form doing double maths, chemistry and biology, but I dropped double maths for single.
You have proper lessons for the EPQ (though I believe they've been moved online) so you get some ideas for what to do, and it's really important you motivate yourself when you do have to do the EPQ.
Honestly, the EPQ was the bane of my existence for year 12, but now that it's out of the way it's a little better now. If you're organised enough it shouldn't be too much of a problem, don't be like me, I didn't stay very organised for the EPQ
sorry if I went off topic