I've had fairly good luck taking them on with groups of Paragons - four Paragons under AI control, with level 20 officers, each set in pairs to escort each other.
This does require the right armament & hull mods, though, and I'd have to go looking for the exact variant I used. Pretty sure it had plasma cannons (forward hardpoints), autopulse lasers, pulse lasers, HVDs, ion cannons (only in the forward two smalls - leave the rest of them empty), hardened shields, accelerated shields, stabilized shields, assorted other hullmods...
This also requires being able to deploy four paragons, which means you really need about eight of the things to make sure you've a large enough fleet to get enough of a share of the total battle size to put all four on the field. (Plus, you need to crank battle size to the max.)
And you'll still lose one every now and again, to a Radiant that happened to get, say, 5x autopulse + 4x harpoon pod + missile specialization.
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Alternatively, if all you really want is to clear out the Remnant presence: sneak in, start a colony (or multiple colonies if appropriate), and then go away. Make sure you stay well away from the system for a while. Build military bases, and the fleets from those will, sooner or later, kill off the remnant fleets and battlestation. (And you keep away from the system so that cargo convoys remain abstracted; this makes them much less vulnerable to remnant interception than if the game is actually keeping track of all the fleets in the system.)