>>14701127 (lb)
Yup. Article I, Section 10, Clause 1 says "No State shall … coin Money; emit Bills of Credit; [or] make any Thing but gold and silver Coin a Tender in Payment of Debts…"
And Congress is implicitly NOT granted the authority to do any of these things except "coin Money" in Article I, Section 8, Clause 5.
Federal Reserve Tokens are NOT permissible under the Constitution.