A-level choices to open up most positions/choices

I genuinely have no idea what I want to do in the future but im decently good in each subject (av grade 7/8) I'm also a very indecisive person and hate the thought of closing up options for myself, so I have decided that Maths, Chem and Geo a-level would open up the most spots for me... does anyone think another combo would?

My go to preference are: Maths, Biology, Chem, Physics, and possibly FM if you have the time.
The sort of degrees that you might not be eligible for include:
To do degrees in these subjects, you would need A Levels in their respective subjects (except for Classics where you are looking at A Levels in Greek, Latin, and/or Classical Civilisation).
See: https://www.mathscareers.org.uk/degree-courses-a-level-mathematics/
What I like about the STEM combo is that it allows you to go into the following subjects:

Then you get to go into any degree that accepts 3 A Levels in any subjects including business, law, and design.
If the fact that you are missing out on some of the humanities and language degrees doesn't bother you, then the combo is brilliant for what it is in my opinion.
If you then consider the option of doing extra A Levels in a gap year to meet any further requirements, then it's going to get a bit muddled. For one, some A Levels would involve coursework and practicals; these would cost quite a bit to do outside of college privately e.g. £1500 for the exams and practicals per A Level. English Lit has an NEA, as well as some of the language A Levels involving speaking and listening elements. Geography and History require coursework. Only the classics related A Levels don't have coursework.
Likewise, science practicals are difficult and expensive to arrange outside of college. Maths on the other hand don't require coursework or have NEA.
There's also the fact that you have yet to mention what sort of career that you want to go into. Not all careers will require a degree, and not all degrees would benefit you when going into any specific career (unless it's in academia). You would need to be specific about what sort of role or sector you think you would like to go into.
The A Level combo that I am recommending should open you to pretty much any professional qualification and apprenticeship that I can think of (unless someone corrects me), so even if you don't want to go to uni you should be pretty safe with those subjects.
On the other hand, if you are not interested in the recommended subjects or you do badly in them, there's little point in picking them for A Level. A Level is typically another step up from GCSEs, and you can't apply the same sort of benchmark and performance you did at GCSE in your A Levels without your grades suffering. You would need a different approach, and things can be more difficult that you intially think.