As regards earnings:
(1) Often the person who chooses to work fewer hours due to 'personal' commitments is in fact saving the state a significant amount of money indirectly. The person who works part time in order to be able to be at home with the kids outside of school hours, or to have time to care for their elderly parent, may be saving the state significant amounts in childcare or social care. (I'm not saying that they SHOULD make these choices in order to save the state money; just that you need to count such factors against the cost of benefits.)
(2) It's not just a matter of how many hours you work: some jobs pay better than others. Some of the differential in pay is due to the value of the jobs; but I don't think it's a strong relationship. Just look at who are and aren't classed as key workers right now: many of those classed as 'essential' are quite low-paid. Rather more of the differential is due to the level of qualifications that you need; and while I think this does need to count toward pay, not everyone is capable of getting a degree, for example. They don't have to be disabled for that; just not to have talents that lie in that direction. I'm not saying that everyone should be paid the same; just that people should not be expected to go without necessities because they don't earn enough to live on: either their employers should pay them a more decent wage, or it needs to be topped up with benefits.
(3) I think it's VERY dangerous to regard people as deserving or undeserving because of whether their illness is due to lifestyle factors ('obesity due to greed') or not. For one thing, most illnesses can be a mixture, and one cannot know in an individual whether their diabetes,for example, is due to obesity 'caused by greed', or to obesity caused by necessary medication, or just to bad luck. Are you going to differentiate between someone who has permanent lung damage from smoking, and one who has it because they spent their childhood in a polluted area, and one who has it because of Covid caught through essential work, and one who has it because of Covid caught through breaking the rules? Are you even ever going to know which it is, in most cases? Anyway, judging and punishing people for their illnesses, whatever the cause, is just cruel.