Don't Know what I'm doing wrong on Zombies Solo Nightmae 4

I'm following guides that tell me what to do I'm sometimes getting luckier than they are but it is still kicking my ass. I played as Jeff had 15K health and a dozen gnashing waters but double Wanda still killed me before I can put up a fight, I try Punisher I get to the Namor fight and he one shots me.

I don't know what I'm doing wrong and was gonna give up but now they've extended it so I gotta give it another go. It takes like an hour to get to the end only for me to be one shot and I don't have that kind of free time. Any help would be appreciated