Here’s my proposal about a simple visibility syntax:

"Solvent": {
  "type": "stringList",
  "values": ["Water", "Acetonitrile", "Benzene", "..."],
  "visibleWhen": { "key": "Solvation Model", "notEquals": "None" }
},
"UV States": {
  "type": "integer",
  "enabledWhen": { "key": "Calculation Type", "in": ["TD-DFT", "EOM-CCSD"] }
}

• Two properties: visibleWhen, enabledWhen
• Operators: equals, notEquals, in, notIn, greaterThan, lessThan. (isChecked is just equals: true.)

I think that handles a large number of cases (e.g., hiding or disabling parts of an input generator)