Best base coat?

Hi! I'm looking for a new base coat. My options are limited to OPI and Sally Hansen (those are the two best brands my country carries). I'm currently using Sally Hansen's Hard As Nails, but I feel it's not doing me any favours. Do you recommend any of the following?

OPI Infinite Shine Gel-Like Base Coat

OPI Natural Base Coat

OPI Nail Envy (not following the suggested application of a coat every day)

Sally Hansen Double Duty

Sally Hansen Nail Growth Miracle

Sally Hansen Miracle Cure

Sally Hansen Diamond Strength

Sally Hansen 7-in-1 Complete Nail Care

Additional info: my nails are very bendy and thin due to some health conditions. They have a hard time retaining polish if not well prepped, and even so they only last 3-4 days without chipping with my current routine (badly prepped can last me, maybe, an hour without chipping or will pop the whole nail polish in a single sheet within a day)