One thing though: what’s the point of using separate keys for work/personal/github/gitlab? I fail to see a practical and security advantage over using one key (per workstation).
These days I prefer to use local VMs to compartmentalize different areas of work (personal, consulting, etc) so my git config is plain and simple. Lately I’ve been doing mostly consulting work around open-source so I’ve been using my primary GH account for the most part, but separate VMs allow me to use a different key (account) without advanced git config incantations.
In fact, I was one of not too many who used separate account for work, and people didn’t understand it, wondering why the hassle.