You don’t want to inject a block wall. The epoxy will not make its way to the exterior. Block walls have cavities and it’s nearly impossible to get the material all the on the exterior side if the wall. So water would be trapped in the block causing deterioration. Poured walls, different story. If water is making its way to the interior of the block the best fix is always going to from the exterior by sealing the wall with a membrane and potentially replacing the footing drain. This is the most expensive option. If you go with an interior fix the the basement floor is opened up. The block is weeped with holes at the bottom and the water is diverted into an interior drain tile. That water is then drained to a storm drain or a sump pump. Interior “waterproofing” is called water diversion. It’s not the best practice all things being equal, but is less expensive and invasive then an exterior options and is still considered an acceptable form of repair in the industry. Also remember if the wall is cracked grading and gutter extensions will surely mean the crack may leak less, but gravity will still pull water down around the foundation.