If you want a "stablecoin", its called VMFXX. https://investor.vanguard.com/investment-products/mutual-fun...
1 VMFXX has been $1 for decades, never budging, never moving. The regulations and infrastructure to support such a thing already exists and have always existed to anyone who has any clue about banks / finances at all.
So why haven't stablecoins been designed to act like MMFs (like VMFXX) ?? Answer: because the cryptocoin community does not want a MMF. Its the only explanation. The cryptocoin community wants 6%, 10%, 18%+ returns on their "stablecoins". And its impossible to do that with MMFs.