Does rental income qualify me for a larger loan?

[Clayton Hepler]

I am looking to move to Eagle County, Colorado next year and I would like to house hack. I want to get the largest loan possible so I can purchase a house hack property with "locked in" units(basically ADUs), renovate the space and also build another ADU or locked in unit so that I can cash flow.

I currently live in a house hack for which I have a $1980 mortgage payment with insurance and taxes and a little over 3000$ in gross income per month. So when I move out I will have about 5000$ gross per month with the 1980 mortgage. Would the bank count this as income for my next house hack?

The question I really want answered is this, how do I qualify for the largest loan possible? What can I do between now and next year besides increase my W2 income to increase my loan amount? I would be looking to use an FHA 203K loan or Fannie Mae Homestyle to get a 700-800K loan with a construction component. How do I know how much I would qualify for? I have a mid 700 credit and so does my fiancé and she makes 90K+ salary and I have a 50K+ Salary with 50K+ in commissions each year that shows up on my W2. So we collectively make almost 200K.

Lastly, I will be moving there next year and will be building more buildings in the mean time. Would this increase my usable income to qualify?