Accidental Landlord - negative cashflow?

[Laurence Fru]

Hey all, 

Due to a change in circumstances, and a poorly (unfortunately) timed purchase of a condo. I'm going to need to rent out my condo. 

For some detail - the unit is worth less than what I paid, and I have a pretty large mortgage on it. The logic is that money is cheap to borrow, and my cash can do more for me if not tied up in the property - but equally, it's in a market that's been hit by Covid a little, and as such I'd rather hold. 

The challenge is that it's a relatively expensive place - and I will be negatively cashflowing around $750-1000 per month / not including any turn over on the property / repairs that would be needed in future. 

The question: 

As someone who has never been a landlord (yet) - is the tax benefit of owning a condo (with property taxes / mortgage interest etc.) going to make it feel better - I'm not counting on it being a hugely appreciating asset - but being based just outside of Manhattan, I am confident for long-term growth. 

When does a negative cashflow make sense? What other things do I need to consider prior to renting? How do people go about renting a single unit typically? 

Basically - I am a complete novice (not originally from the US) and I have no idea how to rent a place here, so I'd love as much advice as possible please. 

Thanks in advance