Well, you say you’re not complaining, but your first post suggests otherwise, or, at the very least disappointment - a small gift “would have been lovely”, asking for help would have “been met with resistance”. Goodness, they aren’t young children, they are adults, but are behaving rather like over indulged children.
You also say they haven’t lifted a finger to help - but have you created this situation by not encouraging them to pull their weight, by not having boundaries and by not fostering a mutual respect? You say you have ongoing daughter issues and your son has adhd, but you know that you can’t allow the situation you have to continue unchallenged - you do them no favours by not giving them some responsibilities. They can’t go on in life living responsibility free for ever - they need to understand that life doesn’t come gift wrapped, all organised and done in a nice package from someone else. You won’t always be around, how on Earth will they cope then without having learned the importance of some independence, some respect and the knowledge that they need to know how to get by in life? They will meet people who will not be as willing to let them sit back and be waited on - they may well encounter strong resistance and be told in no uncertain terms that self centred, selfish behaviour won’t be tolerated - a steep learning curve. You could go some way to mitigate that by becoming a little stricter yourself. It will be hard, but what’s the alternative?