Just try "IFS" with "ARRAYFORULA" & "AND" function to convert units but getting an error message.
Trying the following formula to convert some units. Image is attached of function
=ARRAYFORMULA(IfS(AND(G2="inches",G3="CM"),CONVERT(H2:J2,"in","cm"), AND(G2="inches",G3="mm"),CONVERT(H2:J2,"in","mm"), AND(G2="inches",G3="Meter"),CONVERT(H2:J2,"in","m"), AND(G2="cm",G3="mm"),CONVERT(H2:J2,"cm","mm"), AND(G2="cm",G3="inches"),CONVERT(H2:J2,"cm","in"), AND(G2="cm",G3="Meter"),CONVERT(H2:J2,"cm","m"), AND(G2="mm",G3="cm"),CONVERT(H2:J2,"mm","cm"), AND(G2="mm",G3="inches"),CONVERT(H2:J2,"mm","in"), AND(G2="mm",G3="Meter"),CONVERT(H2:J2,"mm","m"), AND(G2="Meter",G3="inches"),CONVERT(H2:J2,"m","in"), AND(G2="Meter",G3="cm"),CONVERT(H2:J2,"m","cm"), AND(G2="Meter",G3="mm"),CONVERT(H2:J2,"m","mm"), AND(G2="pound",G3="kg"),CONVERT(H2,"lbm","kg"), AND(G2="kg",G3="pound"),CONVERT(H2,"kg","lbm"))) ERROR: "IFS HAS MISMATCH RANGE"