I think feeling overwhelmed is mostly bad time management probably compounded by inability to prioritise/break down tasks and sometimes brain glitches (in my case I think the latter causes the former) and being overwhelmed is having too much to do (how much a person can do depends on the person).

I do define laziness as being able and having the time to do something but just refusing (I conflate all permutations of "I don't feel like it" and straight up just not doing it for no other reason as refusing).

Your method of helping people deal with overwhelm is great, this is why they pay you the big bucks? :)