What do you want to do at a university? If your art BTEC won’t get you there, then it probably would be in your best interest to reapply for courses that match what you want to do, even if it takes another two years, because at least you’ll be where you want to be.*
I don’t do psychology, but from what I’ve heard, it's very interesting, but it just has a lot of content that you need to know, a bit of math, and a few essays. So, if your good at handling lots of content, have decent math skills (and science skills since I’ve heard the papers are very similar to sciences, and there is some biology overlap), and like writing essays, then it’s probably a good subject for you. If not, I don’t think you should let that stop you. If you’re interested enough in the subject, you’ll be willing to put the work in.
I do study history though, and I would say that even though the content and the exams can feel like a lot, I absolutely adore the subject, and I would really recommend it if you're interested because it really does show universities that you're a critical thinker and have good writing skills.
Also, if you decide to take these two, here are some recommendations of subjects to take with them.
Psychology: biology, math, and other social sciences.
History also goes well with social sciences (e.g., politics, economics) but also goes well with other humanities subjects like English.
So, depending on if you're interested in a history/humaties degree or a psychology degree, that should influence your final subject.*
I would just like to add that to do a politics degree, you don’t need A-level politics, so if you don’t pick it and you decide you want to do it at university later, you can still apply. Plus, politics is very historical, so having history will give you a good background anyway.
Economics is the same, and actually a lot of economics degrees actually require math, not economics, so once again that’s something to keep in mind.*
Also, a common combo I have seen is history, English literature, and psychology, so if that’s a combo you think you’d like, then I’d recommend it (but maybe look into it, because I don’t take this combo).*
I do take history, English lit, biology, and chemistry though, so if you have any questions about these subjects, I’d be happy to tell you about them!