Remember actual load rated stamped chain/rigging is service rated for 1/5th of its yield strength.
You're only going to "use " the chains once, if ever. Any 3/8" hardware store chain will keep the trailer attached to the tow vehicle. And honestly, there are 2 schools of thought here.
1 is hitch pops off or breaks or whatever, going straight down a nice road. Safety chains are nice in that they'll maybe keep everything together and get it stopped while minimizing damage.
The other is, you're coming down a winding mtn road with no guard rails or doing 75 around a curve in the freeway and the same thing happens. Do you really want to be connected to your trailer anymore at this point?
I'll take the insurance claim on the trailer over barrel rolling off the freeway with my trailer or plunging to certain death off the Mountian still attached to my beloved camper!
And fwiw, I'm not being sarcastic. There is little chance the trailer is coming off the hitch.
There's already a really small probability you're going to crash your truck and trailer and only a small % of that small probability is from the hitch coming unhooked unless you're an idiot or have a brain fart and don't latch it down.
Poor loading/sway is the greatest contributor and again in that case if the trailer is going left when it leaves the hitch and I'm going right, I'd rather part ways with the trailer.
Unless just towing locally in protected areas, I typically make sure there's a weak link in the safety chain/cable setup.
Like I said, unless going straight when it happens, I want the trailer to be gone, no more, not attached, pretend it was never there in a shtf moment.
Most of my recreational towing is in the second scenario and some of my work towing is as well. I'll take "broken safety chains for $400 Alex,"