Investing in rare earth metals

I've been looking into investing long term into rare earth metals like cobalt, lithium, etc, because their needs will only increase as we need more and more for green tech such as batteries and solar panels

However, looking at a few different options, like Vanguard's Materials ETF, VanEck Rare Earth, etc, my expectation is that they would increase due to higher international demand, but these stocks don't seem to be doing that well

Is this more due to the fact that these companies in these indices aren't doing that well? Or that competition is getting too high?