Took an embarrassingly long 11-ish hours but I managed to finally a hard mode win! I used the damage increase bonus perk for close range and took the final boss out on his first wave with a DBS. It should go without saying but the shield perk, the pan perk that lets you tank one shot every 8 seconds, and all the reload perks are a must especially for hard mode. I got by most of it by using a shotgun and the roll to increase damage 150% perk, and id just try rolling up and shooting as many as I could while they were landing, and that works for most of the levels but in the last couple maps you just need something like a S12K or DBS to shoot everything twice or thrice if it wont go down. I used an MG3 for my secondary/ranged weapon for the last couple maps and it worked really well.
I feel like its a pretty darn good time too, the first time I got to Erangel I was at nearly 50 minutes before I died.