Help deciding A-Level subjects

I am at the stage now where I have to apply to my preferred alevel subjects, I took DT as one of my GCSE subjects and I truly enjoy the subject: theory and practical. I did some research into DT fields and found that I would like to go into a product design career or something similar.
The problem is that I don't know what alevels to pick as the sixth form I want to go to does not give product design or engineering as a subject. They do give Art and design but it is mainly just art and not really dt if it makes sense. I want to pick Maths, Economics and one more subject which woud create a career path towards prodcuct design. I was wondering if I should do sociology but many people advice me against it. What should I pick as my last subject?

Firstly, it seems odd to have a 'favourite' sixth form that doesn't actually offer the A levels you want to do, so you may need to rethink this. Many PD degrees do not have any specific A level subject requirements, but they will require a portfolio.
Are you are more interested in an industry/technology focussed degree - Product Design and Technology BSc | Undergraduate study | Loughborough University requires 'ABB including one from Physics, Maths, Further Maths, Electronics or Computer Science' but this also requires a portfolio of relevant design ideas.
Another route would be to take a 1-year Foundation Art & Design course between school and Uni. This is a very common route for those heading for any sort of Art or Design degree - everything from Architecture to Illustration - and the course is offered at some Universities and many local colleges You do not usually need a formal Art and Design qualification for this course - but you may require a portfolio :
Art & Design Course - UAL Foundation… | Arts University Plymouth
UAL Foundation Diploma in Art & Design — Runshaw College
etc

Are there any other 6th forms/colleges who do do Product design a-level? If so would they be an option?
Also look at the course on unis websites to see if there are any specific subject requirements.
Sociology is actually a good subject.
I did it at both gcse and a-level and loved it.

I don’t know much about DT, but could other art based subjects like graphic design or media be helpful?

Yes, I did think of those but it seems more computer/online based, I'm not sure?

I am at the stage now where I have to apply to my preferred alevel subjects, I took DT as one of my GCSE subjects and I truly enjoy the subject: theory and practical. I did some research into DT fields and found that I would like to go into a product design career or something similar.
The problem is that I don't know what alevels to pick as the sixth form I want to go to does not give product design or engineering as a subject. They do give Art and design but it is mainly just art and not really dt if it makes sense. I want to pick Maths, Economics and one more subject which woud create a career path towards prodcuct design. I was wondering if I should do sociology but many people advice me against it. What should I pick as my last subject?

Yeahh good point, I did graphic design gcse for a year and it was mostly computers like making designs, branding etc, but I think you might be able to make more physical projects since it’s still art and design? I did photography gcse which was mostly digital but I ended up printing my work and doing embroidery so idk if it could be more lenient 🤷*♀️
I just checked and I don’t think media would be that helpful since product design is more stem than I realised so sorry haha 🥲

It’s great that you already know you’re interested in product design! Maths and Economics are solid choices — they’ll help with problem-solving and understanding how products fit into real-world markets.
For your third subject, I'd suggest Computer Science if you prefer something more technical. In this day, you can build digital product very easily. If you enjoy the creative side, Art is another option. Even if it’s more art-focused, you can tailor your projects toward product design and build a portfolio.

I did look for other sixth-forms nearby but couldn't find any that did product design. As the previous person also said I checked requirements but it doesn't specifIcaly ask for product design, atleast one from maths which I plan on doing.
I am considering taking Sociology now thank you, I have never done sociology as a subject so in your opinion what do you mainly learn?