Been there, done that, don’t want the T-shirt.
As has been mentioned upthread, a debt-consolidation loan buys out several high-interest debts with a single debt with a hopefully lower interest rate and monthly payment.
The next step, if needed, is “credit counselling”, in which a counsellor receives money from you, takes over the payments to the creditors, handles all contacts with the creditors to get them off your back, and may negotiate lower payments. In my area (Ontario province, Canada), this was handled by a branch of a social service agency affiliated with the regional government.
Ontario Associaltion of Credit Counselling Services
The next step, if needed, is a “Consumer Proposal”. This is a formal legal document offering to pay back part or all of the debt. In Ontario, the proposal is presented to the creditors, who have a certain amount of time to respond. If they do not respond, the proposal is considered to be accepted. Here you make a payment, but the rest of your affairs and assets remain in your hands.
Beyond this lies formal bankruptcy. This too is a legal procedure, but it has far greater restrictions and implications. Essentially a trustee takes over all of your financial affairs. All of your income and assets go to the trustee for debt repayment except those that you need for survival.
Both the consumer proposal and the bankruptcy are handled by bankruptcy trustees.
As for the OP re credit rating, I was told that, by the time you need these services, your credit rating is already about as bad as it can get, so it doesn’t make a difference from that viewpoint. More important is getting things under control: in other words, survival.
I seem to remember from my credit-card agreements that payments to the cards went to interest first. Each month was treated as a loan, and you paid the interest on that loan, then any additional funds went to reducing the principal.