Use your Contacts
Contacts fills itself in. Every channel you connect feeds it, so the people you deal with appear without you adding them, and each one carries your history: when you last spoke, what it was about, and who said they would do what.
Someone who emails you from work and messages you on Slack is one person, not two half-filled records. When details change in a message, a new title in a signature or a new address on a reply, the record follows.
Your own edits survive. If you correct something by hand, an automatic update will not overwrite it. You can also add someone manually when you need to.
Contacts is not only a list to read. A new contact can start a workflow, a contact can be written into the Brain, and records can be pushed into the system you already keep.