Anytime spokes are radically different in tension effective truing is not possible. Loose spokes and a true rim are a recipe for failure.
Truing depends on an unstressed rim, which you do not have. The wheel was in an accident which physically bent the rim toward one side. The side it's bent toward would have loose spoke, the other side tight ones. Impossible to fix without physically bending the rim back, and unlikely to be fixed event then. This is particularly true if it's not a symetrical bend (U shaped) but more S shaped. The wheel is most likely totaled. Even if a skilled person could make it rideable it will either have poor strength or poor trueness.
The inflated tire was probably helping at least a small amount to hold the wheel a bit straighter, thus the wheel being worse now.