Land Contract Deal

I have an opportunity for a deal but am not sure whether it’s the best use of my cash - all input appreciated! Here’s the scenario:

o Investor is in contract with a person in arrears on taxes on a 5-unit commercial building. 2nd investor (that would be me) can purchase for $40k total which will pay off taxes, pay the investor middleman, and get deed delivered to me. Property will only be sold to an end investor however if they are willing to allow the original seller to stay and purchase back on a Land Contract.
o Land Contract terms: 14% interest only payments for 5 years with escalating balloon based on year of final payoff: Year 1: $48k, Year 2: 53k, Year 3: $58k, Year 4: $63k, Year 5: $68k. If not purchased after 5 years, property is mine free and clear.
o The potential kicker: Property is worth approx. $200k so if the buyer is in default at anytime or after the 5 years, I am not obliged to sell to them and will see a strong return.

My concerns:
o This $160k “profit” will probably never be realized - the buyer would be smarter just to buy back and sell and pocket the extra money so in my mind, I should more or less ignore the market value of the property.
o While I like the monthly cash flow (close to $600/month), I believe I will lose about half of that to taxes as ordinary income (I’m in a high tax bracket). With my other rental properties, I of course can counter my rent/cash flow with paper losses for depreciation and other expenses.
o Because I am entering into a Land Contract immediately after close, I will not be able to roll any profits to another property in the future via a 1031. Rather, I will be taxed which will cut into my sale profits.

Does this sound like a good deal to others? If I’m not missing something, I think I see $3600 after tax (9% after tax return on my $40k investment) + let’s say $8k pretax profit if balloon is paid in year 1 (assume $5k after taxes). That’s $8.6k return on $40k cash = 21.5%. Certainly better than a CD but it’s more a question of what else can I do with that money (e.g. finance rehabs). Thanks for any feedback or suggestions.