Feasability of small-scale pumped hydro

We have a block of land where the house will be basically at the top of a very-approximately 50 metre hill. We will need to collect rain water, and also plan to have the house entirely powered by solar.

An obvious thought is it would be some combination of novel and useful to use any excess solar generation to run a "tiny pumped storage hydro generator" - basically have a rainwater tank collecting rain at the top, dump it down a pipe to a lower tank through a generator, when there is excess power, run a pump to pull water from lower tank back to the house tank.

The land seems a perfect fit - access to the property is from the top of the hill (so logistically easier to get equipment into place), the land is pretty steep (maybe 30-40 degrees slope), and the primary collection is at the top of the system.

I've seen some examples on Youtube of very small scale novelty setups (like charging a phone from water collected in a house gutter), and seen some moderately larger scale examples here in Australia, but if you search around for information on small scale practical examples, you mostly find people internet-yelling on forums.

The gist of the yelling is basically is doesn't scale down well. This is probably true - it appears the problem isn't so much "it doesn't work at small scales", but rather "batteries are pretty good and cheap"

This post on Stack Exchange quotes an now-edited Wikipedia article that

1000 kilograms of water (1 cubic meter) at the top of a 100 meter tower has a potential energy of about 0.272 kWh

which is calculated by [1,000kg*9.81m/s2*100m] convert to kWh which agrees within some rounding errors.

So if we scale that to a common water tank size, 10,000L - we would have about 2.75kWh of potential power. Good.

Problem is:

1. Cheapest I can find such a 10kL tank is about $1500 - quite cheap
2. A random 12.8v battery with 180Ah is vaguely around 2.3kWh and costs $1700 - a Victron LiFePO4 battery, not the most efficient cost-per-capacity brand or battery chemistry.

So even ignoring the efficiency losses with the generator, the infrastructure, piping, pumps, and so on - the idea of using tanks for this doesn't make sense.

I suspect the only way this would make sense is if you had a property with both a large drop, and space to have some form of farm dam at top and bottom.