I value my privacy and use Firefox. Honestly, I have trust issues with volatile “security focused” forks. I feel the risk of them been tampered are greater than the marginal gains.
Does a 7 day expiration matter if the tracker can just set new cookies with new 7 day expiration dates as it tracks you?
Also, Firefox partitions cookies by site (aka Total Cookie Protection), so first-party facebook.com cookies, cross-site facebook.com cookies on example.com, and cross-site facebook.com cookies on example.net all get separate cookie jars.
There's a few ways first party cookies can track you. Probably the biggest single way is Google Analytics which by default uses only first party cookies. Even without cookies at all, GA could track you across the web although first party cookies do make this a little easier and "better". However, first party cookies can help trackers in other ways like for CNAME cloaking[1] which basically makes a first-party cookie function similarly to a third-party one.
Disclosure: I work for a small privacy focused ad company.
> If I get logged out of every website on a weekly basis I'm going to be annoyed.
Then those websites should move to Passkeys.
> How do they use first party cookies to track you?
Because Meta and Google allows websites to submit advertising data to them server side using a self-hosted JS file which sets the first party cookies on your behalf.
This is being abused by advertisers to track you across the web.
If they do care about privacy it would be good for them to copy Safari and make this 7 days.