Have offers, need advice on the next step

So currently I'm year 13, have applied and got offers to do history at Warwick or economics and history at Leeds. I am struggling to choose between the two as Warwick is a more "prestigious" uni but I am looking at going into finance, so whilst Warwick's name may help a tiny bit, I feel like I could be limiting myself by doing only history rather than the history and economics together at Leeds.

Now today I was sitting in class and had a wild thought. My predicted grades are pretty good, so I was thinking that I could accept one of the offers and then on results day see what my results are like. If they're really good (like multiple A*) then I could reject my offers and take a year off to reapply for straight economics next year at top unis like Warwick, which I feel could boost my career chances significantly in the future. I could also get some work experience in the year off and also earn some money to ease the burden of debt. If they're just decent enough grades then I'll accept my offer and go to uni this year.

However, is rejecting my offers the best course of action or will I not be significantly disadvantaged in a future career in finance by doing history or by going to Leeds, which is a good uni but is not the top top tier.

Warwick is a target. I believe you would be fine.
I wouldnt worry about the subject. I would take the offer.

You can also use adjustment, which allows you to ask around in the light of good A levels or a gap can be useful. In limited cases you could ask to change courses.

For adjustment I'd have to reject my offers though wouldn't I? And wouldn't the top unis for economics not have any spaces so they wouldn't be on there anyway?

I'm leaning towards Warwick because as you said it is a target and I feel being more active in terms of searching for opportunities can help negate any "deficit" I may encounter by having a degree in history,