Advice needed - ill during year 12 exams

1.

How seriously would not doing FM reduce my competitiveness? Is it honestly worth putting myself through that hell? I'd have practically no frees once again, uni admission tests, interviews, my maths resit AND harder econ/geog content which I need to ace in order to pull up my iffy AS grades. I'd be doing the equivalent of 6 A levels (econ, geog, maths, AS FM, A2 FM, welshbacc). I'm honestly sick of maths already so would be pretty miserable, but if it's the difference between me getting accepted to Oxford E&M then I'd 100% do it. Also, some unis say they'll accept an A in maths rather than an A* if you achieve an A* in FM.

2.

I'm aware that Oxford want you to sit 3 A2 levels within the same exam period, so if I drop FM and pick up an AS, technically I'd only be sitting A2 geography and economics, but would my resit of 1 of the A2 maths paper (+ an AS paper) count as doing 3 full A2 levels or would they want me to resit the entire maths A2 level?

3.

How will the unis view my plan to resit maths and will this make me less competitive? Should I lower my sights? If I explain in my application that I was ill during the exam period, would universities actually consider this and not just straight up reject me for my low grades? I'm confident that I can achieve A*s overall next year, but I'm worried that universities won't think this based on my AS results which don't accurately represent what I'm capable of.

4.

If I drop FM and pick up AS politics, would this be of any use whatsoever since it isn't a full A level and I won't get my result until after applying to unis anyway? (And of course they wouldn't include an AS grade in their offer).

5.

Should I mention my illness in my personal statement (I believe it's changing to 3 questions from this year onwards) or rely on my college's reference? I'm not too sure how uni applications work yet but I really need to emphasise that this is the cause for my underperformance.