you dont loose your data when a update goes wrong, you just loose access to your data, the update only changes the system partitions on the disks and does not touch you data raid, in such a semi brick it can be enough to add a new extra.lzma to the usb and on next boot it finishes, had that last week with someone accidentally updating to 6.2.2 with a 3615, test version of a new extra.lzma fixed it
so your date are even more safe in a semi brick state of a dsm installtion, no trojan or ransomeware will be able to harm your data :-)))
if my extra.lzma 918+ 6.2.2 loader 1.04b does not work then you cant update for now, you can try if a different nic solves your problem
atm i'm doing 3615/3617 extra.lzma, after this i will revisit the 918+ and look more closely into it