Foundation year or fast track A-Level

I did physics, biology and english at A-Level (don’t judge I didn’t know what I was doing at the time) and I recently realized I’d much rather study physics at university than biology which was my original plan but every physics course requires maths A-level. My first choice university offers a foundation year as an entryway into various physics courses. I have already taken a gap year so it’s important to me to make this decision now: is it a better idea to take a fast track maths A-level course and defer another year or do the foundation year? A fast track course is cheaper but obviously doesn’t guarantee me the grades I need to get into the course I want, which is the better decision?

I did physics, biology and english at A-Level (don’t judge I didn’t know what I was doing at the time) and I recently realized I’d much rather study physics at university than biology which was my original plan but every physics course requires maths A-level. My first choice university offers a foundation year as an entryway into various physics courses. I have already taken a gap year so it’s important to me to make this decision now: is it a better idea to take a fast track maths A-level course and defer another year or do the foundation year? A fast track course is cheaper but obviously doesn’t guarantee me the grades I need to get into the course I want, which is the better decision?

I read this and I just couldn't sit here and not tell you what I know.
I'm in more or less in the same position. Taking Computer science, Biology, Physics at A level.
I'm in year 13, applying for foundation years in physics and, from what I know, I think it's perfectly fine - I also had no idea what I was doing when I started my A-levels, but here we are.
I really want to study physics. If you really want to study physics, take the foundation year.
Foundation years are designed to prepare you for year 1 of your intended course afterwards, so you WILL be ahead of those A*A*A* students, so long as you pass the foundation year.
You will settle into the university before the first years, and you will get accommodation sorted. You will make friends, and be able to start your first year of university with friends.
Taking A-level maths/further maths during a gap year is extremely hard since you will be forced to learn content on your own, unless you get tutoring or something like that.
Don't take foundation years off the table.
And if you finally decide that you just want to take A-level maths instead of the foundation year, still send your UCAS application out. Once you see an offer you might change your mind.
Hope it isn't too late at the time I'm writing this.
Good luck!