PPE at Oxford or Philosophy at Cambridge

I am currently in y12 studying maths, further maths, economics, and philosophy at A-Level. I am at a grammar school now but did my GCSEs at a private school where I got 9x9s and a 9 on further maths (I don't think it counts). I am really interested in philosophy and politics and want to do a degree in those. I have been told by various teachers that doing a degree in those won't count for much unless there from Oxbridge. So, is PPE at Oxford or Philosophy at Cambridge a better option in terms of likelihood of getting an offer and usefulness?

Your GCSEs "count" no matter where you studied them.
A degree in politics and philosophy is worth as much at Oxbridge as at any uni. If you're speaking in terms of employer opinions, the vast majority of graduate employers don't care what subject your degree is in. If you're speaking in terms of pursuing further graduate study in philosophy then in principle which uni you do your philosophy degree in isn't overwhelmingly important as I understand, obviously aim for a rigorous course at an established department, but that includes many unis as well as Oxbridge.
In any event it's worth noting philosophy at Cambridge is a single honours course, albeit it does include options in political philosophy. But you wouldn't be formally studying politics as a field unto itself. Whereas at PPE at Oxford you would be doing so (although you'd also do economics in first year at least, although at Oxford for PPE I gather it's typical to drop to just do 2/3 of the subjects for second and third year).
I think you'd be equally likely to get an offer from either in terms of the information provided so far. Whether you are particularly interested in just philosophy vs a joint honours course and hence your ability to write a suitably motivated personal statement and engage in that material in interview is something you need to determine for yourself.

I am currently in y12 studying maths, further maths, economics, and philosophy at A-Level. I am at a grammar school now but did my GCSEs at a private school where I got 9x9s and a 9 on further maths (I don't think it counts). I am really interested in philosophy and politics and want to do a degree in those. I have been told by various teachers that doing a degree in those won't count for much unless there from Oxbridge. So, is PPE at Oxford or Philosophy at Cambridge a better option in terms of likelihood of getting an offer and usefulness?

I am currently in y12 studying maths, further maths, economics, and philosophy at A-Level. I am at a grammar school now but did my GCSEs at a private school where I got 9x9s and a 9 on further maths (I don't think it counts). I am really interested in philosophy and politics and want to do a degree in those. I have been told by various teachers that doing a degree in those won't count for much unless there from Oxbridge. So, is PPE at Oxford or Philosophy at Cambridge a better option in terms of likelihood of getting an offer and usefulness?

I just applied for philosophy this year, what I'll say is that in terms of postgrad options both courses are brilliant. Studying PPE does give you that extra economics edge, so you could get a good career in that more mathematical or statistical area, but philosophy is still a great course for getting into politics or anything like that and doesn't rule out the mathematically-brained jobs (for want of a better word). PPE is a very competitive course, but from my limited impression I'd say you've got a good chance lmao
The other option is a joint honors, have you considered something like philosophy and maths at oxford? Although I'm not sure that's any "easier" per se to get an offer for.
Basically my point is don't focus on your chances of getting into each course, prioritise picking whichever one you like more and working hard to get in from there. If you really like connecting all the disciplines in PPE, go for it, if you really like analytical philosophy and want to dedicate three years to just that go for it. Spend some time picturing yourself in each place, understanding what you're actually best at, and apply for whatever you want!!
Good luck