Are people in your company moderately technical? If so, I highly recommend https://www.passwordstore.org/ coupled with a PGP key storage dongle (I personally use NitroKey). Then hosting is just a matter of hosting a minuscule git repo per user.

I imagine that a technical company can easily whip up a bespoke simplified interface for its non-technical staff too.

I've used it for about a decade at this point, and it's just perfect.