I have bought 2 new toilets in last year. A Toto and a power flush. They both plug up. The line is clear and the vent is clear. What next?

The line is clear and the vent is clear. if both toilets plug up then something is not clear. How did you determine that they were clear? Back to you, Tom

Eat more roughage? Use less toilet paper with every dump?

I assume this "plugging up" is resolved by using a plunger when it occurs and not having to snake the line out when it happens? If its the latter...then the line really isn't clear and has a partial blockage..