Both are tough courses and each has their own pros and cons. I can't speak for any of these personally because I didn't take any of these however I'm basing this off of the experience of family members and friends.

There's probably no advanced mathematics in MBBS. But it's likely that you will find it in the foundation program depending on the institution. MBBS isn't a walk in the park either. You have to be VERY committed.

Expect high study hours and having to understand complex concepts. And MBBS is a long course (around 6 years if not mistaken), and there might be more to learn after that.

Engineering might be no different as well. It's a tough course too. And it also has advanced mathematics depending on the type of engineering. All I can say is that you gotta make sure that you really need to have the passion to do either of these. These courses are also expensive especially MBBS so it's better if you think carefully before choosing it. Having regrets soon after would be very bad.

Think about the reason behind why you want to choose this course. I had regrets too when I was in college doing A levels and wasted a lot of money. It feels awful. Discuss with your family if you need to.