.- Assume $1,000,000 short-term capital gain  (with other income, so max-tax)Note that before the gain, I was already planning to buy a couple commerical properties (1 in state, 1 out of state), but then due to the gain, I wound up learning about Opportunity Zone investing, QOF/QOZB, etc. -- unfortunately the 2 properties I wanted to buyer are OUTSIDE of their respective states OZ's.

Is the goal just to get a high paying 9-5, create other passive income forms to gain capital and invest?

If you plan to sell the property in the near future, you may want to have a high land value so there’s a lower depreciable property value which would result in a smaller capital gain when you sell the property.

The seller would be responsible for the real estate taxes on the property up until the date of sale (this is normally prorated between the buyer and seller for the year of the sale), as well as any capital gains taxes on the sale of the property. 

Do any of you folks park your cash in Index Funds to try an maximize any gains? 

It will make things less risky for yourself starting out as you gain experience pile on the risk because you know how to avoid costly mistakes.

The taxes are only owed in the event of a sale in the form of capital gains.

Therefore you can only offset passive gains such as stocks and crypto.

There are plenty of posts on OZ and OZ vs 1031, my question is about OZ investment, is it only for capital gains that can be used for OZ investment?

It will cost them nothing so they can only gain from my inexperience.