I think counseling FOR YOU would help you a lot.
Your daughter is over 30 and left for seven years. That doesn't sound like depression to me, as one who suffers from it. I would have been too lethargic and sad to want to travel all over the country while depressed.Doesn't ring true as the cause to me. Drugs, yes. Depression, not so much. Those who READ about depression see that it can cause little motivation and often think "He's depressed!" But it is so much more than that. Usually you do not want to do anything, and that includes not wanting to traipse around the world with a boyfriend for seven years. So I don't know why your daughter won't work, but I won't blame it on depression.
It is good if she gets a job. Do you have proof she is trying hard? Usually you have to apply online so it's easy to check up and see. I am not you, but personally I let my kids make their own money, including my difficult children, and trust me they all got jobs. None of them liked being broke. How long are you going to give her money? Why get paid for trying to get a job? in my opinion only she'll try harder to find one if she isn't getting money from you. What does she use it for? Do you know?
I've been to many, many and mucho even psychiatrists and psychologists who specialize in mood disorders and ALL of them say that you have to force yourself to be active to get better, even with medication. That includes exercise and socializing and I am shy and had to force it. Laying around the house with no goals and no interests will make the depression worse. If you do things for her that she can do herself, like cooking and washing her dishes and clothing, those are activities that would make her get off the couch and be active and the more active you are, the more the depression goes away. So if she is depressed, coddling to it is unhelpful and will only make it worse.
I still think drugs are a part of her life. Maybe a bad drug reaction caused something to snap in her.
There is NOTHING NOTHING NOTHING you can do to make an adult get help. In the US, you can't even make the appointment. The person has to make the appoinmtment. I tried making appointments for my son and they said he had to do it himself. And they asked all sorts of insurance questions that I would not and could not know. so she will have to be the one to take the step. You can go with her if you think THAT will help, but they won't let you in with her unless she agrees.
In the end, the person herself, especially an adult approaching middle age, has to take control of her issues, which you are not sure about. Since you don't know what went on for seven years, she needs to trust her therapist to spill the beans...all of them...and with medication and the right treatment, if she is motivated to do so, she can live a much better life. But mommy love won't do it...in fact, although we don't mean to, we can actually hurt them if we do the things that they can do themselves.
Good luck and hugs for your hurting mommy heart.