I can have a container for my work, personal, project, etc. where Google is logged in, and not commingle any of them, and all of the tabs are a different color, clearly distinguishable from one another. I have containers for separate Microsoft accounts as well. My "normal" tab is not logged in to any Google or Microsoft accounts, because why would I want them tracking me all over the web? Seriously, container tabs is one of the primary reasons I stick with Firefox, and it's FANTASTIC if you have multiple identities you need to manage.
You know all those "my employer G account was closed and now I permanently lost access to my personal one as well"/"an old employee got their yt video flagged and now our Play Store account is inaccessible" etc stories? I'm quite sure this is the mechanism behind those links.
To set a cookie, you just have to add it to the response the server sends back after requests. The browser will then add the cookie upon receiving the response.
https://stackoverflow.com/questions/17769011/how-does-cookie...