Of course, the two thousand Tier 5 combatants -a mix of soldiers, adventurers, and random people who had talent and got to Tier 5 without military training- weren't all the Tier 5's in the city. There were naturally also all the craftsmen and women and people involved in management.
Looking at simple stats, they were stronger than Tier 4 combatants, but their lack of battle experience and little to no training would be a massive disadvantage. Not to mention the lack of mental preparation.
On top of that, throwing them away in war would be beyond stupid.
The creations of the Tier 5 craftsmen and women were far more valuable than the limited help they might be able to offer the front lines. Especially the new and improved cannons that Solvi and the other dwarves have designed.
The design had been shared about a week ago, and everyone was fully focused on making them before the undead reached the city.
I hope the chapters have all been entertaining.