So, save 8 to 10k in taxes, after paying 23k in interest

You don’t “save” money. Example 450,000 home at @6.7% would be 2303 with 20% down. You will be paying around 23k in interest payments a year. There is a cap of 10k reduction due to the salt tax rule, so that would assume, your income would go from 600000 to 590000, saving you a ~ $3,700 plus minus a few hundred in tax liability. Rough estimation, but your spending 23k in order to save ~ 4K.