I'm sure you will have air inside the fuel system.
Bleed the fuel filter.
It will make sense to install a short part of clear hose between filter and injection pump to have a look at it.
The diaphragma inside the pre-filling pump has been discussed. Any drops at the small bore on top of the cover?
Animals with teeth like spikes sometimes like hoses!
It will not conserne a leak by fuel comming out but air comming in when subpresserized.
Hard to find such a suckin`leak.
All bones are crossed.