You don't need FHE for that. It's possible through some zero-knowledge schemes, such as zk-SNARKS, which is implemented in and popularized by shielded transactions on Zcash.
https://sceweb.sce.uhcl.edu/yang/teaching/csci5234WebSecurit...
Chaumian mints are gaining some popularity in the bitcoin world: https://fedimint.org/
(If it's not obvious: Blind signature as such are solid but I wouldn't suggest anyone to give a cent to this sketchy project)
AFAIK (and I'd be thrilled to be proved wrong) we still haven't figured out how to solve double-spend using blind signatures without a blockchain and so the schemes I've seen so far invariably involve either that or a trusted mint and are therefore less interesting to use as currency.
Assuming you already have a base digital currency (like bitcoin), they can still be interesting on/as a higher layer.
[0]: https://xx.network/blog/decrypt-how-david-chaum-went-from-in...