I just started caring about my own privacy. What apps should i get rid of, why and what can i replace it with?

Delete speedtest.net, YouTube, YouTube kids and ChatGPT and use either web apps or favorite them in your browser, as Firefox for iOS is really bad compared to other platforms I would recommend you to use brave instead as it comes included with an adblocker which works really well. Also do you need all of iOS’s bloat ? Do have an Apple Watch ? Do you have an Apple TV+ subscription ? Do you use HomeKit for smart home devices and so on.