What can a seamstress do?

[Usernameismyname01]

Hi. I'm an apple shape - so slim legs, no bum but a thick waist and mum tum

I love the look of chinos style trousers as well as wide leg linen trousers but I find that if I buy them to fit my waist so I'm not bulging over the top and can wear a slim fitted vest top (for instance) they bag around the hip/bum area and generally look a mess

Just wondering if a seamstress would be able to do anything with them and if so, would I be better to buy ones that fitted the waist so legs need narrowing or buy the best fit for the hips/legs/tum and they can do something with extending the waistline

Might be better to get them made from scratch rather than trying to get a ready made pair altered, especially with a waistband & front zip. It’s much easier to alter at the pattern stage.
If you know someone who would make them for you. Enter to discuss it with her first. She could adapt the pattern, make a trial pair out of cheaper fabric to adjust to get the fit right on you, then cut them out of any fabric you wanted. Another advantage would be that she’d then have the pattern to make as many pairs as you wanted instead of having to start from scratch again altering another bought pair.
If you can sew a bit yourself , or would like to learn, you could buy a basic sewing machine & take a course in dressmaking at night class? In fact you wouldn’t need your own machine to start with at some classes