Why can't I use Netflix/Meet/Zoom/etc in Safari anymore?

You may want to try disabling Private Relay temporarily to see if that's what the sites you mentioned are having a problem with. If that ends up being the issue, then I would suggest to stop using those sites that don't value your privacy instead of Safari and Private Relay.

If you are experiencing trouble with Google products you should research its documentation, contact its developer, or participate in a user-to-user Google product support forum. As this is an Apple product support forum, all we can can do is suggest reasons that you are unable to use Netflix/Meet/Zoom/etc in Safari anymore given the minimal information you provided. One of those reasons may be the fact installing the Google Chrome browser results in a multitude of pervasive, automatically updating system modifications that affect nearly every aspect about how a Mac is designed to work. Installing Google Chrome renders it into a full-time information-harvesting and -uploading "bot", and you said yourself that you "honestly hate it". Asking why you use it is not lecturing or "mansplaining" it is a question for which you may have an answer, but you did not provide one.

If you are google-dependent then I sincerely reiterate the need to use something else. If you are required to use Google products then don't use a Mac.

Is there any setting I should not be using that Sequoia defaults to?

Maybe, but the problems you describe are very broad in nature. Consider using EtreCheck and posting its report in a reply to this Discussion. Instructions: How to use the Add Text Feature When Posting Large Amounts of Text, i.e. an Etrecheck Report - Apple Community. The behavior you describe is decidedly abnormal, so if you are interested in fixing your Mac more information is required. EtreCheck often provides some actionable information.

No one needs Chrome.

Can you explain the reasons you have grown dependent on it? I am confused how updating macOS could be related to that, and how that dependence may be mitigated. Especially since you hate it.

I do not use Chrome, but Netflix and Zoom are not having any trouble with Safari here. VPNs could be a factor, so if you use one, don't. That might explain your difficulties. But if you really require Chrome, sell your Mac and buy a Chromebook. You're wasting money on a Mac.

But no one needs Chrome.