Universities don't really expect people to have 4 alevels. I dont really recall seeing any universities that specifically say they'd have a preference for 4 alevels. And it may be overwhelming with the amount of work.
I'd personally say an EPQ is better. Having an EPQ often boosts your ucas application and can result in your offer being lowered by a few grades. And is far easier than an alevel.
You may want to take a look at the entry requirements for the University's you're wanting to study at and see if they acknowledge the EPQ. And look at the preferred subjects of the course you want to study