OctoPrint version, OctoPi version, printer, firmware, browser, operating system, ... as much data as possible
Version 0.18.0, running on Raspberry Pi 3 Model B Plus Rev 1.3
Jayers Marlin 2.0.1
Ender 3 V2
Chrome
Windows 10
Typically the controls are disabled like that if the printer isn't connected. Since this a UI issue I suspect something weird going on browser side. Does the same thing happen in incognito mode of your browser? Do you see any errors in your browser's developer tools (F12) on the console tab on initial page load?
Additionally (though not related to the problem in the post) your Pi is reporting that it is overheating and throttling, you should try and move it somewhere/do something so it will stay cooler.