@adifferenttruth Alternate practical advice:
Accept that your clients will all be like this.
Triple your fee, with a view to dropping your clients by two-thirds (which I'm guessing you could handle without so much stress).
Some will drop off immediately, awesome. Then of the others that accept your new pricing, fire the most problematic ones till you've reached your target number of clients.
Then lean-in to the work you do for those remaining clients, wow them, manage their eccentricities, look past their shortcomings, under-promise and over-deliver.
For the future, you can set up a waiting-list for your services, and only take someone on if an existing client leaves.
Exclusivity is your friend. You're making this change so you can focus more fully on meeting 'their' needs. If they choose to accept you new rates, they can be sure of getting exceptional service from you.
FWIW, I've done this, albeit in a different context. Scary as heck, but I was surprised that most clients didn't bat an eyelid; in fact some had been wondering why I was originally so 'cheap' and had felt like they'd somehow been taking advantage of me. Go-figure, wish I'd done it a decade earlier :-/