I need a members area adding to my website

I’m a Performance Nutritionist and I have a website with Wix.

I had a members areas designed using Wix, but it has been plagued with bugs since it was built, rendering it almost unusable.

I’m looking for a more permanent solution where my clients can have a personal log in to their profile and I can upload goals for them weekly. I need to be able to add document and links to their profiles, and they need to be able to track their weight and progress pictures etc.

I know nothing about how this could be completed, so I’m looking for some advice about a solution that would require minimal upkeep and monthly costs where possible.

Because my members area at the moment has so many issues, I really need a relatively quick turnaround if possible.

I’m also unsure of costing for this sort of thing, so I’m very open to offers there.