Is this similar to what you're using?
https://www.amazon.com/MroMax-Compression-Spring-Printer-Electric/dp/B07Z4QD2HL
There's some others that seem quite a bit longer. The one linked seems to match yours.
Sorry, never messed with springs before.
These die springs: MroMax 3D Printer Die Spring 20mm... https://www.amazon.com/dp/B07Z4QD2HL?ref=ppx_pop_mob_ap_share
The green ones are quite a bit stiffer than the stock elastomers.