Are you using XR? You may have better brand to brand consistency with an XR generic since it is a more complex formulation inside the capsule.
As noted above, also note the brand each time you fill an Rx. It is true a particular brand may have an issue for you but it is uncommon. A pharmacy can get a different generic for you to try. Switching generics wont affect insurance and pharmacies should comply with your request plus you wont need an updated prescription from the doc. They may resist only because they get better pricing from some companies over others and they will have to eat the difference (they shouldn’t make you pay extra for a different brand generic).
I find it very helpful to take dose holidays 1-2 days/week too.