I feel your pain OP. My last apartment had one toilet different than the others and due to its shape it would collect the most heinous shit streaks. I’m vegan so 95% of what I eat is, ‘roughage,’ as suggested above. It didn’t matter. Everyday: shit streaks. I eventually started using Clorox pucks, the type that go in the toilet tank, and they worked a bit. There are also toilet scrubbers out there that are less disgusting than traditional scrubbers that seem to hold moisture and detritus. I’m curious to try they toilet paper landing strip suggested above. I wish you the best in all future defecations.