I'd get 2 round chainrings * , and keep the rest. the BB can be modernized to a new cartridge type without discarding the crank arms..

* 130 will take a 38t smallest, though 39t is quite commonly used..

Square taper Cranks are quite modern you can buy new ones currently.


External bearing BB's screw in place of the cups of your BB ..
then slip a 24mm tube spindle through them, that tube is inseparable from the right/drive crankarm.



./.