Clogged toilet, daughter put cardboard roll from toilet tissue, may have been two, tried plunging, remove what came up, snake used, now water is lower, may have issue further in system, and why is water level lower? Thank you

The blockage is still within the bowl. Get 5' auger and snake that bowl several times ( or many times). Keep flushing until blockage is cleared.

If that doesn't help, you will have to remove toilet, flip it upside down and reach inside to remove the obstruction.