By the way, I don't really understand what you mean by free energy, if it uses solar energy, I don't think it's free either because it still requires maintenance costs and capital to build it. So, what do you mean by free energy?
Above I showed using the RTX 4090 as an example that GPU mining is unprofitable even with free electricity. Free electricity is electricity that costs 0 cents. If you pay for electricity, then mining will only be profitable for YouTube bloggers who shoot content and earn money from advertising.
I don't think so, I think there is still an advantage to mining using the latest gpu like the RTX 4090 that you mentioned, although the profit is very small, and this is different
from last years where people still got profit when mining using gpu or even cpu. And as I said before, there is a need to mine token or coin that has potential, in order to get big profit in the future. Just to add, if op still a beginner, maybe you can try mining using a CPU first, because it feels a bit of a loss to try using a GPU straight away, especially using the most sophisticated one.