Land could be real estate, which, if not just sitting idle, it's still the epitome of rent-seeking.

Plus, land rented to farmers is productive because of the farmers, not because of the land -- and would still be a sinkhole of money from the middle class (the farmers) to the rich person doing the renting, not entering circulation like the money a farmer would make (to buy animal food, seeds, whatever, and to live their family).

You know that a large proportion of the returns from the stockmarket are made by reinvesting dividends.

"rent seeking" seems to either be used by people who don't understand how trade/investment works or want something or subsidies'

or its a dog whistle that tends to go with gold bugs, cryptocurrency fantasists and then on to much less pleasant things

Err, "rent seeking" is an established term of mainstream economics and well studied.

Not sure what you're going about re: gold bugs, and "less pleasant things"...