Contrary to the pp who suggested a family meeting to agree ground rules, I would pick them off one by one and have those conversations. I have three teen DCs and although they are mostly lovely and do pull their weight at home there is a tendency for them to 'gang up' when together and if you have no support this will be stressful. Stop bearing yourself up about the past, you can't change this. You can change how you operate as a family in the future so that you are happier and your teens know what to expect.
We started with a non negotiable weekly job for each, e.g. DS cleans the family bathroom every Sunday. There are other chores such as loading the dishwasher, emptying the bin, putting the recycling out, that we rotate around the three so everyone has a turn. Everyone chooses and cooks one meal per week. This could be jacket potatoes and beans or a full on roast. I dont care as long as everyone takes a turn. I also adopt a mindset that noone is doing favours for me, or 'helping' me by doing household tasks or sorting their own shit out. They are participating in family life and learning to be independent.
Each teen is responsible for their own rooms, putting washing in basket, changing sheets, keeping it tidy. I pick my battles here. One DD is very tidy , the other's room is like a war zone, DS is somewhere in between although he lives at uni most of the time. If they choose to live in mess, that is their issue now. If they run out of clean clothes, that's their problem, not mine.
The other part is shutting down any disrespectful language straight away. Dont engage emotionally, as difficult as this is, dont let them know you are hurt. Just calmly reinforce your expectations, 'I am your mother, and I expect you to treat me with respect', or 'I expect everyone who lives in his house to contribute to the chores'. Walk away if needed, dont get into a fight. Come back to the same conversation when they are more reasonable. I find teens benefit from the same kind of consistency as toddlers. Ensure any rewards/sanctions are proportionate. Changing the wifi code until they have done whatever you have asked is reasonable (if you can be arsed), confiscating all of their devices for a week is not.