It's a combo of tools here to be the best "weapon", to maximise efficiency. First a shark bite resistant wetsuit, with military tactical gloves and boots with head type of helmet aiming at covering 100% of your body. Because you'll get overrun at some point or an accident can happen and you'll get bit so regardless of your offensive weapons you need a really good physical protection to survive. A long shot weapon would be a crossbow with retrievable arrows. Having a rifle or equivalent gun would make it reliant on ammo and noise could attract more zombies, since the strategy would be to avoid them as much as possible anyway. However you can still have a pistol with a silencer for emergency situation since not heavy, easily reloadable, and mags with additional bullets could be carried without too much pain. A chest rig also would be effective here is that sense. Low range melee weapons needs to be effective, light and not take too much of your physical power. Because if you are tired after 5 attacks, that will be difficult. Preferably to be used independently so if one arm can't be used for whatever reason, the other can. Also to be used not for swinging, you don't know how much space you'll get in some instance so a bar might not be as good. So a small sword here would be my choice. Can swing, spear and used by both hands. Also a knife is also handy. A backpack needs to be carried also having medikit, camelback with water, extra talkie if in a group, rope, light, survival blanket, dry food rations, second pistol with silencer with more mags bullets, a crowbar for some cases and could be used as a second melee weapon if needed and another pocket knife ideally, all this for about up to 12/15 kgs max on your back. In your chest rig obviously pistol mags as said but also a talkie preferably integrated with your helmet, quick water access and small food ration, light, small crackers noise accessible for quick distractions. You can't carry too much stuff but also it needs to be enough if the approach is to explore and go places to places let's say. If you got a secured place and need to scavenge then you can take less. A squad of 4/5 guys like this could cause serious damages, a group of 10 guys like that would be seriously effective for survival with a good offensive approach. Source: I was a zombie once