Our other rentals in completely different areas, we have a duplex in Penfield (east side suburb, our primary residence) and a duplex in the south wedge.

Pay attention to whether the room is a primary suite (your own bathroom) or shared bathroom, how many roommates, etc. as those would factor in to how much someone would be willing to pay.

A house hack for a primary residence for about two years and then you could repeat this again. 

I recently took out a Heloc on my primary home to do a repair and consolidate some debt.

I bought from a primary homeowner in Indianapolis metro area who took really good care of this home (I did live in this house and rented it out when I moved back to California) and from a flipper in Indy more recently.As far as primary homeowners, they can range from taking really good care of the house to someone who has a lot of deferred maintenance - I renovated a local property that had a lot of issues.  

I am definitely referring to a house that was already insured as a rental, not as a primary residence.

However, a huge portion of the extra monthly payments would be offset by new rental income from my current primary residence.

Went to a community College for diploma, then worked, interned and got hired in her field of study before graduating college with a bachelor's last month with no debts in a growing field with high demand and six figure yearly salary.She bought a primary residence 2020 with 3% down and house hacked, which allowed her to live rent free for 2 years while tenants paid down the loan.

But if it’s money out of pocket for down payment (primary vs investment) there are definitely ways around that.

If your primary has a net $1M appreciation you’ll only pay $100k cap gains tax - that’s a lower alternative than what you propose.