You could of course put a hole through the middle of the rack tab for the cable to pass through with the tab abutting the fork.
But generally the top rack tap is just to stabilise rather than a load carrier per se.
It did occur to me to do that, but I think ultimately it’s more faff than I’m willing to accept! As long as, as you say, it’s not particularly high load-bearing then hopefully the current bodge will be fine.
You could of course put a hole through the middle of the rack tab for the cable to pass through with the tab abutting the fork.
But generally the top rack tap is just to stabilise rather than a load carrier per se.