With work experience it’s quality over quantity. There’s not a set amount you need. Instead focus on getting enough experience so you feel as though you’ve got a realistic insight in to Medicine and you’re able to reflect on the roles of a doctor, skills required in medicine and also understand some of the challenges.
If you want to have a look at the work experience I applied to medical school with you can check out my pre-med journey in which I have summarised it all. I feel like I had quite a lot of work experience, so don’t be put off by the quantity. You can have a few really good experiences that you reflect really well on and that’ll be more than enough.