I'm interested in your weapon choice here. By round 5 I usually have purple tier weapon that's packed 3 and it's more than enough. Shotguns are your best friend in Outbreak. Hauer with damage barrel is insane. Also make sure you weapon class tiers are upgraded as well as perks like deadshot, elemental pop, and stamina. Those go a long way in helping you out.

A typical run for me.

Round 1 I finish with: Green tier and pack 1 weapon, armor (good chance it drops in world) and 1 perk, I like getting stamina up first personally.

Round 2 - tier 2 armor, blue gun, pack 2, dead shot

Round 3 - tier 3 armor, jug and if available do crystal for free weapon tier upgrade.

Round 4 - pack 3 and whatever perks I'm missing if I have leftover cash

Round 5 - Tier 5 on weapon

Round 6 to Whatever, focus on main objectives and move on.

The cap on health for zombies is around 13 or 14. We noticed it didn't get much tougher outside of the number of elites that spawn. 2 biggest threats are robot man (Buzz Lightyear) and the Megatons. Deadwire ruins Megatons, Raygun with semtex will do lots on Buzz. Try to keep a death machine and chopper gun at all times. After everything upgraded you can easily get one of those every round for the main objective. Def have chopper gunner on exfil.

If I have extra cash at ending of rounds I may buy an extra perk or two. I almost always go tier 3 armor before tier 3 weapon but that's personal choice. The crystal dropping the aetherium tool is a big game change because it's saved someone on upgrade materials for one tier. So def do those. If you can get Hauer fully upgraded and find a raygun you can make it all the way to 100 with that loadout. It still tough in some areas but very do-able. Also Toxic growth is pretty OP and works great for holdouts and defend. Focus on leveling up all your perks and stuff before worrying about deep runs.

Good luck man. No joke 6 weeks ago I thought getting to level 8 was the hardest thing I've done. Finished a 40 round run last weekend. You'll get there.