Answer based on context:

Aside from acquiring the lower Tenasserim coast, the Burmese did not achieve their larger objectives of taming Siam and securing their peripheral regions. The actual outcome was the opposite. The new energetic Siamese leadership was now better able to support rebellions in Lan Na and Lower Burma. On the other hand, the Burmese offensive military capability was greatly diminished after two long wars with Siam and China. In the following years, Hsinbyushin was totally preoccupied with yet another Chinese invasion. At any rate, the Burmese could not blame the Siamese for fomenting the rebellions of the 1770s. It was mainly the warlord behaviour of Burmese commanders who "were drunk with victory" that incited the rebellions. The Siamese were only helping the ready situation on the ground. In 1773, the southern Burmese army command provoked a mutiny by its ethnic Mon troops and put down the mutiny with "undue severity". Over 3,000 Mon troops and their families fled to Siam, and joined the Siamese army. The army command warlord's behaviour only grew in 1774 when Hsinbyushin suffered from a debilitating long illness that would ultimately claim his life two years later. Local governors began to disregard the king's royal orders, an unimaginable development only a few years previously. In January 1775, another Lan Na rebellion started with full Siamese support. Chiang Mai fell on 15 January 1775. Hsinbyushin on his deathbed ordered his last invasion of Siam in 1775. The Siamese defences held this time. The Burmese armies were bogged down in central Siam in June 1776 when they withdrew after the news of Hsinbyushin's death had reached the front. Lan Na was firmly on the Siamese camp. The over two century Burmese rule of Lan Na had come to an end.

How many wars diminished the Burmese army?
2