You'll be lucky to find anyone to work on it.
Pre-Installed MacOS:8.6, Maximum MacOS:X 10.3.9
https://everymac.com/systems/apple/imac/specs/imac_333.html
2Z691-4908-A iMac G4 & iMac G5 PPC OS X 10.3.6 (Panther)
Disk 1 2Z691-5259-A
Disk 2 2Z691-4908-A
Notes
2Z691-4908-A
Compatibility
iBook ClamShell, iBook (Dual USB), iBook (Late 2001), iBook (14.1 LCD), iBook (16 VRAM), iBook (14.1 LCD 16 VRAM), iBook (Opaque 16 VRAM), iBook (32 VRAM), iBook (14.1 LCD 32 VRAM), iBook (800/900 MHz 32 VRAM), iBook (14.1 LCD 900MHz 32 VRAM), Except - iBook G4 (Mid 2005), all iMac Flavor, all iMac Flat Panel, iMac G5 (17-inch), iMac G5 (20-inch), Mac Mini (original), Power Macintosh G3, Macintosh Server G3, Power Mac G4 & Macintosh Server G4 - all models, Power Mac G5--all models Except - (Power Mac G5 (Early 2005), Power Mac G5 (Late 2005), PowerBook G3 (Bronze Keyboard), PowerBook G4 - all models Except - PowerBook G4 (Double-Layer SD), Xserve G5, Xserve G5 (Cluster Node), Xserve G5 (January 2005), Xserve G5 (January 2005 Cluster Node)
PowerMac G5 OS X 10.3.4 (Panther) Software Install DVD
Item #:
2Z691-5094-A 1000949
Compatible with eMac (ATI Graphics), eMac (1.0 GHz G4), eMac (USB 2.0), iBook ClamShell, iBook (Dual USB), iBook (Late 2001), iBook (14.1 LCD), iBook (16 VRAM), iBook (14.1 LCD 16 VRAM), iBook (Opaque 16 VRAM), iBook (32 VRAM), iBook (14.1 LCD 32 VRAM), iBook (800/900 MHz 32 VRAM), iBook (14.1 LCD 900MHz 32 VRAM), Except - iBook G4 (Mid 2005), all iMac Flavor, all iMac Flat Panel, iMac G5 (17-inch), iMac G5 (20-inch), Mac Mini (original), Power Macintosh G3, Macintosh Server G3, Power Mac G4 & Macintosh Server G4 - all models, Power Mac G5--all models Except - (Power Mac G5 (Early 2005), Power Mac G5 (Late 2005), PowerBook G3 (Bronze Keyboard), PowerBook G4 - all models Except - PowerBook G4 (Double-Layer SD), Xserve G5, Xserve G5 (Cluster Node), Xserve G5 (January 2005), Xserve G5 (January 2005 Cluster Node)