> all the tax affordances related to owning real estate vs. equities
The only ones I can think of are depreciation (analogous to capital loss harvesting), 1031 exchanges (loosely analogous to step-up basis; this is the biggest difference) and opportunity zones (analogous to QSBS).
If you borrow against your equities, you can deduct the interest paid on that. That mortgage-interest deductions are bigger is a function of the lending being federally guaranteed more than tax law.