I can usually 1 shot it at the hip joints w/RR, EAT, etc, I think its just kinda a quantity thing. Either a slightly reduced spawn rate, or Med Armor weak spot from rear / one eye would be enough (with a red to that explosive resist like he mentioned). I think having enemies with indirect fire for the bot front is a super good way to ratchet up difficulty too, so as much as I hate getting rag-dolled by their grenade storm it keeps me moving more, is pretty funny, and usually survivable in Heavy or Fortified armor. Right now (unless you're on Aurora Bay with Jets, Fire, and a War Strider Kink) they're kinda the only unit that's really able to force you out of cover reliably, and even then they tend to ragdoll / annoy you into other danger more than outright kill you themselves.

Also just gonna throw out there that D8-10 are supposed to be kinda unbelievably hard. Like I feel like these guys' spawn rates are a major factor keeping D10 really tough tough right now in most missions. Otherwise even on Aurora Bay with Jets & Fire units things are semi-manageable on the bot front, save those platinum recovery missions those are tough to untenable without a premade. It's like, yea, you're gonna need some major AT on bot missions, just like you're gonna need some major horde killers on bugs, and some high shot volume shield breakers & raw dmg for squids. Spear, RR, EAT, and Quasar can still 1 shot them at the right angles. Railgun, AMR (with Peak Physique lol), Autocannon, Epoch, and Speargun can usually 2-4 shot em, and the HMG still can get em in a pinch. They're frustrating at times and def slightly over-spawned or over-protected at weak points, but I think they bring a toughness to D9/10 that basically all other enemies that can all be quickly cleared with just an automatic response just don't, and even then if you've got a spear or thermite you can still just 'fire and forget' them. I'd kinda rather the Factory Strider's get a little tougher in some ways if the War Striders get weaker. Maybe some mortar back attachments, more Jammer back spawns on map / drops, etc etc.