Hah, no worries. That's a BIT big of a topic for an r/empirepowers post. But if you want, you can look up some of my stuff from r/askhistorians where I'm a flared Tibet & Bhutan/Vajrayana Buddhism contributor. Otherwise I highly suggest you check out Omair Ahmad's "The Kingdom at the Centre of the World" which is a really great primer for Karma Phuntsho's "The History of Bhutan" which is an exceptional history book by an Oxford education native who takes a critical view of his country, its history, and its institutions.
ANYWAY, I got really excited to do r/empirepowers particularly because Bhutan not only achieved its "independence" in 1616 but by around 1650 started becoming a nation all its own. (Bhutan was never really under Tibetan dominion. Prior to 1642 everything between the Himalayas and the Gansu Corridor was a loose collection of states that were largely run by local Buddhist teachers, tribal chieftains, and Mongol warlords. The valleys of Bhutan were just a part of this mosaic until 1616.)
Anyway, in 1616, my ruler the Zhabdrung Ngawang Namgyal fled from his home of Ralung in Tibet south to Bhutan. Tibet was becoming dominate by the Geluk school of Buddhism, the Zhabdrung claimed to be the head of the Drukpa Kagyu school and was fighting a rival claimant. He successfully escaped and began a nation-building process of constructing various dzongs (castles) all across the (western half of the) country. It wasn't until after his death in 1651 that the Zhabdrung's subordinates - namely Migyur Tenpa - expanded Bhutan to the western half of the country by subjugating and vassalizing the chiefs and teachers in the east. Migyur Tenpa and his successors continued the Zhabdrung's work and built dzongs in the east.
The latter half of the 17th Century was a key development period for Bhutan. They constructed most of the dzongs that you can still see in the country. Further refined the Drukpa Kagyu school away from Gelukpa interference. Bhutan's most famous temple - Paro Taktsang, "the Tiger's Nest" - was built in this era by the great Tenzin Rabgye. Also, the 17th Century involved six (six!) wars from Tibet and their Mongol allies to try and defeat the Zhabdrung's religious rebellion. The first two wars were from the Zhabdrung's rival claimant at Ralung. The succeeding four were under the 5th Dalai Lama's government who had succeeded in allying with the Khoshuud Mongols who became the military arm of the Ganden Phodrang (the Dalai Lama's government). The 5th Dalai Lama also happened to be the cousin to the Zhabdrung's rival now seated at Ralung, and also claiming to run the Drukpa Kagyu religion. Bhutanese armies and dzongs defeated the Tibetan-Mongol alliance all six times. Only the 7th invasion in 1730 was mildly successful, which was hardly an invasion, but was focused on humiliating Bhutan rather than bringing Bhutan into the control of Lhasa. Bhutan paid Tibet some money and then was concerned with its own affairs for quite some time.
That said, this era was also one that planted the many seeds of instability that would plunge Bhutan into centuries of internecine warfare. The Zhabdrung - unlike the Dalai Lamas - wanted to pass his title through heredity, not through reincarnation (his rival was the reincarnated claimant). But his son was an invalid (it is currently believed his son had a stroke early in life) and had only one daughter prior to the Zhabdrung's death, and one afterward who only lived to be 15 or so before she died of the plague. After that, three reincarnated claimants appeared which, of course, did nothing to help Bhutan's political stability.
Obviously, there's a lot more to it. But that's a good starting point. I wanted to build more dzongs, expand both east AND west (Migyur Tenpa wanted Bhutan to expand all the way to Ladakh) and hopefully take back my ancestral lands in Ralung... BUT why not? Just take Lhasa and the remainder of Tibet. Recreate the Tibetan Empire of Songtsen Gampo. Anyway... yep. Still wondering if it's worth laying that groundwork I already started.