This is tricky, and I can hear that you’re trying to honour who she is and what she wants while starting to feel that it’s unsustainable. I’m going to make some suggestions, but please don’t hear me as saying ‘you can solve this alone’. I’m describing things you can do because you are the one talking to us. She should definitely be listening to you and supporting necessary changes.
Would she be able to hear your concerns better if she thought it was a temporary situation? You could say, for example, that you know how much she liked her freelance work, and how disappointed she is that the algorithms are penalising her business. Then suggest that ‘while we wait for things to pick up, could we reorganise a few of our bills to make sure we stay out of debt.’
You could mention that you would be happy to do some home economies- try a cheaper supermarket, have meat free Mondays, cut alcohol out of the shop.
If it’s a short term thing, she may feel less threatened. It may also encourage her to work at the business or find freelance again.
You may need to start mentioning, ‘we can’t afford it this month’, occasionally, to make real that this isn’t you being tight, this is a current problem.
Given the age of your DC, she may be in the throws of menopause. That can be massively challenging, more anxiety, less self esteem, bad sleep, loss of identity knowing you’re no longer fertile… let alone basic comfort issues. Don’t suggest that as she may take it as an accusation! I had no idea my issues were menopause related until a friend suggested I look into it. I just felt useless, and overwhelmed by everything.
I’m really sorry you are having a hard time, and hope you find some support while you work your way through this. There aren’t many people able to support a family on one wage, these days. It’s not on you, it’s the current world.