the first Kernel that came via update and wouldn't boot was 4.16.11 so I always removed the latest one before updating to keep two working versions, but as the problem persists with 4.16.12, 4.16.13, 4.16.14, I guess that's a permanent change (unfortunately I don't know how to install Kernel 4.16.9 or 4.16.10 two check when exactly that change occured).

During boot there's some kind of error message shown:
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This might be related my GA-AX370-Gaming 5 mainboard that caused problems from the start and wouldn't even allow installing fedora without setting acpi=no.