Can't boot into or mount Mojave APFS partition after repartitioning for Linux
I've had exactly the same issue on an older MBP running 10.13.6.  I've tried twice to work around it and got your problem.
In the end (both times) I had to do a recovery using internet recovery (option-command-r) and then restore my stuff from Time Machine.
I looked at rEFInd but didn't install it, so I can't say how to drive it.
It seems that APFS doesn't like to be messed with.  I'm looking at dropping the APFS and just living with the old journaled FS as a fixed size partition.
After that, I figure I can tinker with the EFI partition until I get it right.