Would you consider adding support for domain-specific overrides (e.g., open *.notion.site links with Chrome but other URLs with Safari) in future versions?
For Google Drive links I open a picker that lets me choose from two chrome profiles and incognito.
https://www.hammerspoon.org/Spoons/URLDispatcher.html
Here's a cleaned up version of my config... I also mapped global cmd-shift-1/2/i to focus my profile and incognito windows (and create a window if none already existed):
https://gist.github.com/beaugunderson/d1ca2218b9b272f3ac3573...
Check back in a week!
As a kind of apology, I made a drop-in hammerspoon config that should accomplish exactly what you wanted: https://gist.github.com/philocalyst/ad9f6d7cc08a9cdefa795e1b...
And if you've never used it before: https://www.hammerspoon.org/go/