I do not like the idea of self-hosting VaultWarden because I generally do not like the idea of application software requiring so much random access memory for even the simplest tasks. So, my idea was to use something like pass[0] or passage[1] (pass[0] + age[2]) on a remote server, but the problem arises when Yubikeys come into play.

I am in no way, shape, or form, endorsing this PonyApp thingy and cannot vouch for it as I haven't audited it. But judging by what it says on the tin, it does appear like a candidate to solve the specific problem I have.

[0]: https://www.passwordstore.org/

[1]: https://github.com/FiloSottile/passage

[2]: https://github.com/FiloSottile/age