I think you need to sit down with them, when you are not feeling frazzled, and have a very honest conversation.
Explain this is your home that you have worked hard to pay for and decorate and organise in a way that works for you. They are welcome to continue living in it if they truly don't feel they can afford a place of their own but from now on, it has to be with consistent respect for your house rules. And if they don;t like those rules, they need to look for a place of their own.
The rules are that they always pick up after themselves and if they forget, so you have to remind them, they never treat this as nagging but apologise and immediately do the job they left undone. Twice a week, they each cook healthy, balanced family meals that they shop for, and they ensure the food is on the table at a reasonable hour and they prioritise doing this on nights when it is their job. They also help wash up and clean the kitchen after they have cooked, so they learn not to use every pan in the house to create a mediocre pasta dish.
They each have two days when the washing machine is theirs and they need to keep on top of their laundry.
They each spend two hours a week on general household jobs like cleaning bathrooms, hoovering, washing windows, mowing lawns, bog grocery shops.
They split all household bills with you: council tax, utilities, TV subscriptions etc. In fact, to improve their credit rating, they should each become the named bill-payer of one or more of the key utilities. They pay and they ask you for your share.
Explain that none of this is you being controlling. It is you devolving the overwhelming number of responsibilities of running a home so that it is shared equally between three adults. It's not to make life miserable for them, but to ensure they are living like responsible adults and not treating you as the default adult as you are exhausted. Tell them it starts today, right now, and if the system isn't working by the end of the month, they have three months to find a home of their own, and you will help them find somewhere.