You will need to have a rental agreement (tenant ready to move in) in place. The lender for your new home will count the negative cash flow from the condo as debt when calculating your ratios to buy the new home. If you don't have a renter ready, the entire mortgage, taxes, and HOA dues will count against you as debt and possibly ruin any qualification despite having great income and credit.
It is not necessary to have 30% down payment to buy a new principal residence. If your credit is excellent, income is consistent and sufficient to handle the new mortgage, taxes, and insurance; then you may be able to purchase a new home to move into with as little as 3% down on an FHA loan.
There are always limitations on financing. FHA loans can only go up to $729,750 That essentially puts you at a $750K limit with the lowest down payment. If you put down $70K then you would be able to do FHA and purchase at $800K. FHA loans have expensive mortgage insurance (up to 1.75% of the amount of the loan - in this case almost $13,000). But they offer the opportunity to buy with less than 20% down. You do not necessarily have to pay that yourself. Depending on how negotiations go on your new purchase, you may be able to get the seller to give you credits for closing costs, fees, points, etc. If you get a credit for points and fees from the seller, there is still a tax benefit for you in writing those costs off as part of your purchase.
You need a very good lender (I know one) and a very good CPA (I know one or two) to handle the complexity of what you are doing. Bad lenders and trying to do your own taxes at this point can cost your dearly down the road.
There are also loans available with 15% down that would be conventional (not FHA) and carry cheaper mortgage insurance.
You have lots of options.