I did a mini study last year that was an extension of some of the tastytrade strangle work. I was trying to figure out what was the most efficient use of capital on both a percentage basis and ROC. I only did it with a few tickers and specifically was looking at use of margin and buying power reduction selling various options. I looked at uso, spy, dia, qqq, gld, and iwm against the futures or the index. It was fairly extensive so to keep it simple will just show /es/spy/spx. Here is the quick summary and it was true for the others with the exception of qqq, the futures options were not liquid enough in that.

Selling delta 8 options 45 DTE. Keep in mind spy was under 200 and the vix was around 14-15 so the #s are different today.
I looked at how much money it would require to actually cover the position or at least avoid a margin call.
SPY needs about $6000 per contract to cover a large move without a margin call
SPX needs about $40,000 per contract to cover
/ES needs about $6000 per contract to cover
What this means. From a percentage standpoint SPY actually wins but from a ROC /ES is the more efficient product because you are selling higher premiums. From a strangle standpoint SPX is the worst and tastytrade also did a study that found spy is more efficient than spx because of the tighter bid/ask spreads. However, there is a tax advantage and volume advantage to spx or /es.

What I take from this is if you have a smaller account stick with spy, medium account move up to /es and if you have a private jet trade spx or /es.
For those that do not know the ratio 10 SPY = 1 SPX = 2 /ES contracts.

Interestingly the most efficient market from a percentage basis was /CL oil futures requiring only about $4000 per contract. Just watch the leverage on any of them, that is the only thing that has ever cost me on trades gone bad. Now I always keep enough cash to cover the position in a black swan event.

Hope that helps, cheers, Chris