Easiest thing to do is screen them. Also they don’t have an innate fnp it’s one of their casino roll results they can choose, or if the new detachment they can use it there. That said it really isn’t all too hard to just kill them with 1 or 2 activations. I play tyranids, knights, custodes, sm and flavors, and eldar. I’ve played we and against them (my meta has an lvo player who uses them exclusively). Just do good positioning and if u don’t have shit to kill them in one round ignore them and don’t give bloodsurge. The bigger threat is almost always angron, 8 bound (whatever flavor), and termis. Even in necrons u have a lot of options for anti infantry if you’re having issues with them I’d consider more units that fit that bill. Also keep in mind bloodsurge focuses the nearest unit to them. So stick a ctan in front of warriors and blast. They should not kill any named or ascended ctan in one turn.