unsure about what a-levels i should pick

my first choices were: biology, sociology and french, since i'm good (ish) at all three and i have no idea of what i wanna do at uni/as a job. dentistry sounds alright, but i'm trash at chem and maths and those are obvious requirements to get into that industry. same thing with med in general.

anthropology seems interesting, but what jobs could i get with a degree in that?

You can get the same jobs with an anthropology degree as a degree in essentially any other traditionally academic subject such as physics, history, economics, etc. Most graduates don't do anything related to their degree when they graduate, and most graduate schemes don't have any subject requirements or preferences when it comes to your undergrad degree. You could just as well go into media, the civil service, banking, accounting, law, or any of the wide range of generalist business/management grad schemes with an anthropology degree (or Egyptology or philosophy or plant sciences, etc, etc). The most important thing will be to get appropriate work experience through internships etc during your degree, and ideally also engage in societies and so on and hold leadership positions within them (e.g. treasurer, officer roles, etc) which you can use to demonstrate what relevant employable skills you have and how you use them "in action".

I think taking jobs into consideration while picking your A Levels is quite unnecessary. Most jobs would prefer you to have more employable education such as uni degrees/apprenticeships. Plus, I literally had no idea what I wanted to do post-18 when I was picking my A Levels. Having a broad range of subjects is always a good idea if you aren't sure (I for example picked Maths, Economics, and Film Studies).

I would also suggest picking EPQ if that's an option at your college - universities love seeing an EPQ in your application so they might lower the grade requirements.

At the end of the day, it's up to you, but make sure you make the right decision since it is not like GCSE's

Psychology? It fits with bio and sociology well and you could go on to study psychology or behavioural science.
Law? No subject reuqirements just grades
International relations - maybe with french too!

Depends on your interests and motivations. What interest you and what do you see yourself doing in the future?

epq sounds good on paper but a lot of work, which i don't know if i can handle