I've been able to press into that style of line on some other vehicles by repurposing a line flaring tool. Basically after cutting the rigid plastic line the tool can be used to press barbed or other style of fittings.View attachment 2855
I dont think this will work on the fuel line by the tank
And up by the engine, as i edited my previous question, i fear about fire risk.
do you know where the check valve is on the fuel pump assembly? If its on the bottom, then there could be a bad hose on the fuel pump module that goes from the check valve to the top. if its on the top, theres a chance you could fix it by removing from the tank and ensuring the sock is clean and the hose is in good shape and the outlet pipes arent leaking.
The check-valve is internal to the assembly from all the information I've seen. Mine flows perfectly, just doesn't work as a one-way anymore to prevent pressure drop during cranking.