It depends how you define ‘destroy Tyr’. Physically destroy the city or simply kill most/all of its populace to fuel his transformation.
In 2nd Ed, the first 6 Defiler Metamorphosis spells required a total of 9,000HD of living creatures. (3 x1,000HD, 3 x 2,000HD), plus some more complicated higher level creatures to fuel stages VII - IX. Extrapolate out the higher level HD sacrifices, add or multiply even more HD to account for the fact this is a 10-in-1 ritual, and to be honest, I don’t think draining most or all of Tyr’s extended population of 40,000 is unrealistic. However, even if only say 50% of that 40,000 was intended as fuel, there’s another factor: draconic rage.
There’s also the question of would Kalak have retained his sanity? If yes, then there might have been 10-20,000 people left in Tyr after Kalak’s ascension. If no, they’d have been drained in his indiscriminate rage.
We know from Borys, Kalid-Ma, and Abalach-Re that multi-stage transformations are risky, but generally successful, but in every case the ascended dragon has gone beserk (in Borys’ case at least a Kings Age, in the other two instances KM didn’t survive and AR couldn’t maintain the transformation long enough to find out their rage durations). Borys’ rampage turned the Tablelands into a desert. KM obliterated almost all of his/her own city.
Kalak knew this - he was there when Borys went mad and helped put down KM. The way he wrecked Tyr’s society and economy to finish his ziggurat (risking war with Hamanu to do so) suggests he really didn’t care what was left of Tyr when he finished.
In conclusion, I think there’s a considerable body of evidence to suggest Kalak did intend to destroy Tyr, or at the very least, didn’t give a hurrum beetle about what would be left after he was done.