If you didn’t get a response from the carb cleaner check (not super unusual), I think it might be worth doing some additional diagnosis before pulling things apart.
Sometimes an unlit propane torch works better at locating a leak. You might have to temporarily remove the fan belt and run it that way for the duration of the test.
A vacuum leak that is bad enough to cause the terrible idle you are describing, should be one you can locate. If another round of tests still comes up empty….it’d be good to start exploring other theories. Ignition system would be the next place I’d look.
