I use Next A LOT - this is a common question/concern but is actually totally normal and working as expected. Next is letting you know code is being injected.
This happens often when you have browser extensions that modify code after next hydrates it which is why sometimes it is flagged as a hydration warning.
The obvious flag here is Date.now and Math.random, these are clearly not in your new app and is common code used in extensions.
start removing chrome extensions such as Grammerly, css color pickers, or things like json converters that overlay the page etc.
If you do not have extensions like this then just remove them one by one (you can add them back easy). You'll notice that when you remove them, the error will no longer exist.
As soon as you find the extension causing the issue then simply disable it or do not use it while debugging your application.