Yes the fifth Dalai Lama was very powerfull and sometimes a hard ruler like we know in history regarding Kagyu.
But he has also another side, which shows his great interest in Dzogchen.
Yes the fifth Dalai Lama knew what was nice/good.
Nevertheless we have in Gelug no authentic Dzogchen lineage i guess, or am i misunderstood?
Well, Ngawang Lobsang Gyatso or the 5th Dalai Lama, was born in 1617 to descendants of the royal house of Zahor.
Out of the chaos of 17th century Central Asia, he emerged in 1642 with the whole land of Tibet from Ladakh to Tachienlu under his rule.
The 5th Dalai Lama was prophesied in certain termas as an emanation of
the enlightened activity of King Trisong Detsen. He felt a deep connection with the Nyingma tradition of Guru Padmasambhava, and had a number of important Nyingma teachers, such as Zurchen Chöying Rangdrol, Khöntön Paljor Lhundrup, and Terdak Lingpa, Minling Terchen Gyurmé Dorje.
He was particularly close to the masters of the ‘Northern Treasure’ lineage of Rigdzin Gödem, who appear frequently in his visions. In his autobiography he also speaks of Pema Rigdzin, the first Dzogchen Rinpoche, whom he urged to found the Dzogchen monastery in Kham; he calls him "the great Dzogchenpa who has totally understood the Nyingtik".
Dudjom Rinpoche writes: Of particular interest is the manner in which the Dalai Lama received the teachings contained in the ‘Profound Pure Visions’, which was foretold in a prophecy in the termas of the glorious Tashi Topgyal:
You who are now king of the black-headed race,
Through pure aspirations, your 5th incarnation will reveal
‘25’—with five special mind treasures.
he wrote down the 25 sections of teaching called Sangwa Gyachen— ’Bearing the Seal of Secrecy’.
As many of you know, this Sangwa Gyachen cycle forms part of a larger tradition, the Secret Mantra teachings of the Nyingma or Ancient school of Tibetan Buddhism. The rituals and practices of this school are transmitted in 3 ways—
the extensive lineage of kama,
the shorter lineage of terma
the profound transmission through pure visions— dak nang.
The Sangwa Gyachen cycle consists of transmissions which have their origin
in these pure visions.
Now pure visions can be considered from 2 points of view.
First, there are meditative experiences of a more ephemeral kind, known in Tibetan as nyam.
Then there are the pure visions in which a master actually experiences receiving the transmission from a deity in a pure realm, and this is considered to be quite different from a meditative experience.
This cycle of pure visions of Sangwa Gyachen comes down to us from the
5th Dalai Lama.
Among these 25 sections, the principal one focuses on the Kagyé, or
‘8 Commands,’ where all the deities appear in a single mandala. Individual practices also exist for each of these deities. The whole cycle of Sangwa Gyachen contains a number of empowerments, blessings, and permission ceremonies for different deities, both peaceful and wrathful,
The Klu Kang temple was built by the 5th Dalai Lama and here we can see the Dzogchen murals about Yogis with their Thogal visions. So it is quite evident that the 5th Dalai Lama was very interested in Dzogchen.
Best wishes for our individual practice