So are you sugesting something like this?
I think that would work, the issue would be then connecting compression to LDPE, and would need an ferrule to prevent colapse. I think I have found some 4mm OD ferrules too that should work
https://www.aliexpress.com/item/1005007168229307.html
Good day
I recently had my water chiller connector pop off and nearly flood the kitchen overnight. After investigating the failure, it seems that the 90degree John Guest quick connectors are not meant to be used on Stainless steel tube on the output of my water chiller...