iATKOS Inside: Good OS for 21.5” 2015 iMac i5 cpu and 8gb ram?(Cant upgrade the hardware) every os except for using windows 11 pro on a separate partition it just too slow for the imac to handle.

Good OS for 21.5” 2015 iMac i5 cpu and 8gb ram?(Cant upgrade the hardware) every os except for using windows 11 pro on a separate partition it just too slow for the imac to handle.