consider a lighter tire with smaller knobs / less rolling resistance
back in the day installed 24x1.75 Intense micro knobbies on some of my kid’s 24” bikes (pictured above)
don’t know if this particular tire is still available - but other similar 24” bmx race type tires should be available
Tioga Powerblock wire-bead would be the lightest, fastest, cheapest option going with BMX race tires. There actually isn't a lot of top tires available in cruiser size (24"), most are 20" only.