Alternatively, house hacking a small multifamily could cover living expenses while building equity.

Buck up, find alternatives, research before you leap, be smart. 

Those that own real estate will want to be active, those who are limited experience and time look at it as an alternative investment and want an expert to manage it just like some hire a financial advisor for their stock portfolio.

Alternatively if you feel confident in the higher value, I would ask if the lender is open to doing an independent appraisal ordered by an AMC instead of a desktop one. 

If managing the STR is no longer sustainable @Robbie Shiver, here are a few alternative options to explore:Mid-Term Rentals: Consider marketing to travel nurses or corporate relocations for stays of 1-6 months.

As an alternative, would a cash-out refinance, a home equity loan, or a HELOC make sense for you?

I would not invest in real estate with a retirement account.Its too much of a headache and likely not that much better as an investment alternative within a retirement account1) Real Estate provides tax benefits for individuals who own them.

Things have to go really bad from here, as I see it, for the office to underperform alternatives in the next few years, from a cash flow perspective. 

Therefore, I have a hard time committing to a house hack which contributes greatly to my problem of raising capital for a conventional mortgage with a 20%+ down payment instead of alternatives such as an FHA. 

Alternative options include offering a significant down payment, a lease-option agreement, a joint venture, or a deferred closing to align with John's timeline.