I'm thinking of picking up some parts or using an old laptop to host a few services, passbolt being one of them. I've seen that it requires an SMTP server though. Is this actually required? And would I be able to use this without getting a domain name?
I don't have an answer to your question, but out of curiosity why passbolt over vaultwarden (the non-commercial bitwarden backend)? It's the most common thing I hear about in this space, what makes you prefer passbolt?