I can sell the units hopefully for about 840,000 before realtor fees of 5 percent and whatever I'll be taxed on.

Basically trying to get the most tax benefits and protection as possible.

Seller financing does not always sell for more money and if there are big price declines then you may end up having to forecloseMy recommendation is to sell it with borrower getting traditional financing and put that $ in a tax friendlier account than loan interest = ordinary income rates

I live abroad in Bermuda and I'm currently unable to buy property there due to restrictions and transaction taxes.

We file our taxes jointly.  

Tax deductible improvements such as drainage tile, terracing, irrigation can significantly improve the productivity and the value of the land.

If you have rental income, do you already have your 2023 taxes filed? 

The mortgages and closing expense can be written off to eliminate the taxes as you want 

I know the question doesn't involve tax bracket, age etc. 

If I did not report expense for my 2023 tax, how would I write off my huge expense (~20K) for my future profit then?