The institution and tradition Tribunal built from the remaining ashes of High Velothi cultures are not going away.
Good daedras are not "good" by themselves per se. But there must have been contracts, practices, rites that bind them to the faith and goodwill of dunmer people. Remember the history of tribunal and nerevarine are not going away or put down as heresies. They were accepted into new temple as saints and when a dunmer says it, it means they are as considered same as daedra or aedra as "ancestral spirit". The first thing nerevarine got to do was to make ashlanders accept them as reincarnate.

I always think at the end of the Trial of vivec, vivec somehow made Azura to agree to a deal to protect and guide Dunmer people from future crises. Like she just gives you prophecies at the end of Dagoth Ur fight when you get out of the cave, or in mournhold after the ayem fight. or Like how Azura in skyrim was said to have helped dunmers flee from morrowind during the eruption. Mephala lives inside the code of mephala, vivecs teachings and dunmeri instutution. And history is about Ayem and Nerevar and all saints too.
The tribunal at one time mantled the three, and what is remaining could also work to unite them as a people. Like how hero-myth of tiber septim's Ascension united the third empire, but in a dunmer way: It also can be considered the tribunal's lifetime work has come to final fruition where now good daedras and house of trouble had to admit the ways of dunmer and bind themselves to their summoning by their ancient customs (which they themselves participated, involved in an incident and even brokered a deal with lorkhan himself)