Once you start accumulating a good amount of real estate, apps like mint or monarch can't handle the sheer volume of mortgages, credit cards, banks etc.

Given the size of the income you are working with in semi-retirement, one would assume that you do have substantial capital to work with, or at the very least can accumulate it fairly quickly, so on top of just real estate tax savings strategies, you would also likely benefit from a team who has subject matter experts in estate and gift planning. 

Additionally, it enables you to capitalize on opportunities quickly without waiting to accumulate sufficient personal funds, thus maximizing your growth potential and taking advantage of favorable market conditions.

If you buy in a location with significant and sustained population growth, you can use a cash-out refinance to reinvest accumulated equity as the down payment on additional properties.

I am debating whether to use a dedicated business account that is funded to ensure proper tax records vs using a personal credit card so I can accumulate points. 

If they have a higher income, they are likely living large and accumulating more debt; but as a landlord your main concern is will they pay the bills and take care of your rental.

Also lets say we accumulate 2 primary in 5 years, we can alway sell because appreciation would kick in ( lets say 5 percent times 5) so equity building is enough to do this in loop cycle.We can do this :    a---->b----->c----a---->d---->c :-) lolit's seriously the highest R/R tax-advantaged strategy we could have in real estate.

But, for property managers working on owner's behalf, there isn't a way to be able to modify chart of accounts both for property manager to track operational expenses and for owners to track mortgage payments, insurance payments, accumulated amortization, depreciation and improvements.

But don't despair because although this is the case when you look at it myopically, in reality most investors go into multiple deals accumulating 100s of thousands of passive activity losses in their first few years investing.

How long will it take before the accumulated appreciation, outgain the accumulated negative CF?