If I had the option to keep my personal and work notes in the same vault, I’d do that for simplicity.
However, I cannot take my work specific notes with me when I leave a job so I use two vaults.
In my work vault, kept only in company machines and destroyed on the last day at work, I keep track of my work projects, meetings, tasks and write my running notes.
Everything that is general knowledge or can be turned into general knowledge, I regularly write in my personal vault that is meant to be my life-long notes system.
If I learn something new that is not specific to a system at work, I document it into my personal vault.
If it’s something I consider valuable enough (eg. something I’d need at work in future), I may keep a duplicate note in my work vault for linking from my daily or meeting notes.
It has served me really well. It guarantees I don’t accidentally store material I shouldn’t have access to after a job ends and it makes it easy to destroy the work vault without losing anything super valuable.
Most of the real valuable stuff is somewhat straight-forward to generalise to be stored in the personal vault.