I couldn't tell from the link, but does it let me run two profiles side by side?

This is the only thing that makes FF awkward for me when not using a Mac.

Yes. With the extension, you can launch any other profile and a new window under that profile will be opened. There is no limit to the number of profiles that can be simultaneously active. The extension menu also lets you add, remove, and edit profiles.

Thank you, I'm going to add this.

You can bookmark about:profiles and click "Launch profile in new browser" under each profile to open it in a new Firefox window.

If you are using GNOME desktop you can also try this to integrate the profiles into the launcher. I wrote it when still using Ubuntu but I'm on Fedora now and it's the exact same steps: https://www.tombrossman.com/blog/2020/launch-firefox-profile...

this would fall under the "awkward" way of changing profiles.