How do I lower the water level in a toilet bowl
Usually water level is determined by the height of the siphon bottom. Any liquid higher than that will drain to sewer line. That's not adjustable on a toilet, as it's in the shape of the porcelain tubing cast into the stool. You should be able to kludge things to a lower lever by adding a piece of flexible tubing which goes drops further into the bowl, and the waste line than does the original porcelain. However, that's going to be problematic, as it'll be prone to clogging and make the toilet harder to clean.
Only real option is to replace the toilet with one that behaves as you want. Some extra tall toilets give more room between the seat and the water level.