There are still a lot of good unis that ask for A*AA including maths, but they don't ask for the A* to be in maths specifically. Places like Bristol, Notts, Bath, Durham, etc. So you'd still be able to get into these good unis without an A* in maths.
But to answer your stated question, I imagine PPE from Warwick wouldn't put you at a noticable disadvanatge for grad jobs relative to most top economics degrees, obviously career outcomes largely depend on the individual in question and not just the degree. The helpful thing about PPE is that whilst it's obviously less focused than straight economics, the vast majority of economist grad schemes state that they require at least 50% of your modules to be in econ, and this can be achieved via PPE if you pick econ as one of the two specialisms in 2nd year and then econ as the single specialism in final year. Therefore, generally PPE students can access most of the econ grad schemes that straight econ can, plus all the non-degree subject specific grad schemes that straight econ people can as well obviously.
For most divisions, investment banks don't have any requirements over the subject you study during your degree, so PPE is more than fine, I worked with people in IB that did music/classics/english, etc degrees. Although naturally there are some specific roles where you wouldn't really be eligible (although straight econ applicants wouldn't either), this will be things like quantitatve research and most trading roles (prefer STEM grads) and then other obvious ones like Legal, technology, etc. So PPE definitely doesn't put you at a disadvantage for banking grad schemes for the vast majority of graduate roles.
In terms of what jobs you can get, well it's completely open. I've never ever seen a single job that requires a PPE degree. So the graduate schemes that PPE people go into are the sort of grad schemes that anyone can apply to (other than econ grad schemes, as PPE can go into these whilst students from degree subjects other than econ related ones generally can't apply to these). So there's a massive variety of roles that PPE people can go into, more than I can list. However, generally PPE students at good unis (e.g. Warwick) tend to go into stuff like banking, consulting, accounting, finance, think tanks, politics, the civil service, sometimes law after doing what used to be the GDL and LPC route, quite a few go into the business grad schemes at Fast Moving Consumer Goods (FMCG) firms which are good. But as I said, PPE people can go into most econ grad schemes plus any grad scheme that doesn't have a specific subject requirement (which is probably 90%+ of grad schemes).