SOLVED: Why does my controller randomly presses buttons? - DualShock 3 - iFixit
PlayStation Controller Repair - iFixit
DualShock 3 - PS3 Developer wiki
Steam Deck natively recognizes the PS3 controller. Simply plug it in via USB, wait for Steam OS to recognize it, then unplug USB cable and it will work over Bluetooth without needing to pair it. : r/SteamDeck