Disclaimer: I'm not a Necro player, so the below may all be perceived bullshit.

In my view too many Necro players come in with the mindset they need a full army before they can fight.

Necros with a perfect army easily overpowers most 1v1 (some exceptions aside but all builds have the rock to their scissors) and a necro with no army struggles in most 1v1s.

The reality is Necros are in a constant tug of war to fight when they're strongest whilst everyone else is trying to weaken them before the engagement. This means summoning zombies, etc.

IMO you shouldn't always be walking around with a perfect army, the challenge is maintaining the best army you can and choosing your engagements based on what you have.

If you spend 2 hours in the middle of nowhere rebuilding a perfect army each time you lose it you're asking for frustration. However regularly engaging with a couple of solid zombies is good enough for all but hard counters and vet pkers (which you avoid until ready).