Siege anchors defense (top Def +4,680% & HP +4,851%); Ranged leads attack (+5,162%). Attack trails Defense/HP on every branch except Ranged — raising Attack buffs is the lever that turns your proven defense into offense.
The gap your report doesn't show: a K49 anvil needs siege ATTACK (a cited example runs ~5,500% in-city siege attack) plus ~1,600% enemy siege-HP debuff to KILL what it tanks — not just survive.
Mandatory on the wall general — a ring/bracer with +15% siege attack range, or enemy siege outranges your anvil and fires first.
6-piece Humility Blazon (siege-defense) + Military Academy (finish in-city/defending siege, then enemy siege HP/Def debuff branches) + best in-city Castle Decoration — the only sources of the "Defending" buff.
Zhou Yu is #1 overall; the cleanest pure-siege main is Takenaka Shigeharu paired with Stephen II. You already own strong wall defenders.
The WALL set: +1,170% total, in-city Def/HP +25%, +50% owned in-city ranged/siege attack. (Heian is for siege ATTACK marches, not the wall.)
Achaemenidae→Parthian debuff gear, siege HP/Def-debuff mayors (Zhu Di, Montezuma I), Russian Epic culture (trap +15%). "Automatic fight for other Cities" ON — and keep troops in each sub or its debuff stops firing.
Nandi (defensive hybrid: ranged/siege atk +104%, in-city ground HP +130%) or Behemoth King (pure siege +52/52/52) on the defender; debuff beasts on the mayors.
Maintain traps for the Russian trap bonus (secondary now). Layer siege: T13 as the thickest damage line, T14 as cover, T9–T11 as supporting depth.
Your Def/HP is already whale-proven (held 161.9B power). The needle-movers now are offense-side: in-city siege attack, enemy siege HP/Def debuffs, and the +15% siege range bracer — plus flat Def/HP that enemy debuffs can’t halve.