Have you tried fencing pliers? The cutting notch on the side is a bypass cutter.
https://channellock.com/product/85/ I always use them for cutting heavier gauge wire, like tying up corner braces.
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For relatively soft wire, Klein Lineman's pliers, but I have ruined more than one set cutting something too hard. But that's on me. Also, don't use a Leatherman. Especially if the wire is still energized. Not only does it tingle a bit, but the arcing ruins the jaws...
I have ruined fencing pliers, too, but those were usually a cheap knock-off brand.