Check out Precursor (FPGA device with softcore CPU running on it for trustability).
Xous (microkernel OS for Precursor) has an application called Vault that does FIDO2/U2F as well as password management and USB HID emulation.
https://www.crowdsupply.com/sutajio-kosagi/precursor/updates...
Much more on the dev board side and probably overkill for just this purpose but a really cool device.