I had a Cocker that went thru that. Her CHF was misdiagnosed, so by the time she got meds for it, her abdomen was like a water balloon. Vet drained about 2 lbs of fluid off her, and she went from lethargic and not eating, to playing with her toys and eating and being normal. Kept her on Lasix, and 2 heart meds, and 2 weeks later she ballooned up again/stopped eating, so drained again. Ended up needing to drain her weekly, and each time, she sprang back. After about 3 months, she no longer got the swelling in her abdomen, but instead her lungs got fluid in them, and she stopped eating. I put her down then.
After going through that, I always swore, I would never do that to a dog again. I think I kept her going for me, not because of what was best for her. So, yes, the draining and meds can buy you time. If she is ok with going to the vet often, then, it can buy time, when combined with meds. But it won't buy much time, and you need to realize that the time will come, when the fluid will not build in the abdomen, but instead start filling the lungs. You do not want to see a dog suffocate. And it seems to come on that way pretty quickly. So you need to be aware, and have access to a vet 24/7. They don't generally just die peacefully in their sleep when they have CHF.
Sending you hugs, because putting a pet down, and making the decision of when is awful.