@Dylan Grieve - Thanks for sharing, even if it's painful. You have a short-term problem first and foremost. If you decided to keep it, how do you get out of that high-interest debt asap so it doesn't bleed you to death? Doing a cash-out refi will get you 75%-80% LTV (not sure exactly what lenders are doing at the moment, but I was at 75% 6 months ago) So that means you have a chunk of cash that's at 4% and some that's at 12%. Are your negative cash flow calculations taking that into account?
The next question, assume your negative cash-flow those numbers above, can you afford it?
On my first property in 2005, I was naive and took too much bad advice and bought a house at the height of the market that broke even with a tenant renting back. Only to find out the tenant was paying way too much and when they moved out, I'd be losing $500 a month. The market soon dropped and I was underwater. I was stuck, but I worked and paid that difference. I still own the property today. It cash flows and has appreciated well above any money I've put into it.
If you can afford to support the property, it's hard to stop appreciation if you have a long view. Especially with the inflation, we're seeing.
My 2 cents, yrmv!