Sounds like u are not following the news. US and the west is aggressively trying to setup rare earth production and processing plant. Rare earth production is not all that technically advanced. its just energy consuming and dirty in terms of pollution. They will just accept those difficulties and produce rare earth anyway. Moreover, they can just offload rare earth refining to a poorer country like India. I would say China has about 5 years before rare-earth leverage is completely gone.
Consider what China will look like in 5 years time.
1. China's modern military capability will roughly be double what it is today, given observed/probable production rates
2. By then, it should be pretty obvious that China can "rolfstomp" over the First Island China, irrespective of whatever the US can do
3. In semiconductors, DUV machines (economically optimal for 70% of demand) should be well into mass production, and EUV machines (the other 30%) should at least be in pilot production
4. In almost all other tech sectors, foreign imported components should have been replaced by domestic alternatives
5. China will be even more dominant in new sectors such as Solar, Wind, Batteries, electric vehicles, 6G telecoms, etc. We can expect China to have caught up to world-class in biotech and also in the areas of AI where it lags
If there is a time to play the rare-earths card, it is now.