Lister has better resistances (including phys), hp regen etc.
I assure you nothing is one-shotting Lister (though he can still die to a tier5 ~conc+AD herald pack, but slower)
I'm also not sure where your info is from that they have same HP?
patch notes said max demon hp is now capped depending on demon type and I'm sure Listers cap is higher than an A5 spearwoman
I've used both plenty post-patch and Lister is very clearly much tankier
Spearwomen only have 33% dr / 2 regen, lister has 50% / 0 regen, urdars have 55% / 4 regen or 75% / 3 regen
Spearwoman type is capped at 80190 in P8, Lister is capped at 121500 (hephasto same cap), since base HP for their types is capped at 12540+660*PX for spearwomen, 19000+1000*PX for superuniques, then 450% scaling is applied afterwards, then blood oath at the start of the game, then battle orders, all multiplicative. The elemental resistances are mostly irrelevant since they all get +77%ish from blood oath, so they're all immune to fire/cold/light, though only lister is immune to poison, which is irrelevant because all poison does is disable regen and he has 0 regen. Without stone skin its 49% dr for spearwoman, 71/91% urdar, 66% lister
Spearwomen have 5957-8564 base HP in TZ96 and 11914-17128 for uniques, so it depends on the RNG roll (which you really can't see) that they'll have 53613-77076 base HP, just below the 80190 cap
Even a 1 point blood oath build gets ~1205% hp oath and 89% bo, so around 660k-950k hp for a trash mob lancer, 1.3m-1.9m for a unique lancer, I'm not 100% sure on urdar cap but I think its around the same ~2-3 million that it will reach whether normal or unique, and 3m for lister
The point of all this is that these numbers are astronomically high and if anything
could one-shot a bound demon, its just going to kill a 50% tankier bound demon before you react anyway.
I leveled all the way from 89 to 98 with a trash mob lancer and the lancer never died a single time (nor did I), then I ate it at 98 to try to farm a unique lancer replacement, gave up and got another trash mob lancer and finished leveling to 99 and it hasn't died once.
There is nothing in the game capable of killing any of these bound demons if you don't just go afk with them tanking 30 might+conc+cursed enemies for 30 seconds, and if you did, no monster would be tanky enough because amp damage gives the full -100% even if you get a stone skin immune.
Lister winds up being more vulnerable and less resilient simply because he's not regenerating back the HP you sap from blood boil, which makes him a liability if you're incautious or spamming heavily against a herald. An urdar is pretty much identical to lister except with 2.44% HP/s to offset blood boil even without engorge, and adds some crushing blow not that it really matters. Same movement speed, same AI, same stun attack, same size, same damage, same attack speed. Though yes lister has some extra AR, not that it matters with conviction aura.