My headcanon that bleeds into all my other headcanons is that the two years after Crepus's death/Diluc's departure could go down as one of the worst times in Mondstadt's recent history.
A prestigious clan, an entire family that played vital roles in their society for decades if not centuries, gone in one night. The head of the clan dead, the eldest MIA, and the youngest suddenly renounced the clan. The biggest player in the alcohol industry that Teyvat has to offer now has no real figurehead, and though we know that Elzer ended up picking up the pieces, it for sure took a couple years to truly reach smooth sailing again.
That's in the economics stand point.
Social is even worse. Crepus was an active member of Mondstadt, he visited the church, he was friends with many many high ranking people of all organisations (Varka, Cyrus, Seamus, Frederica, etc). His death would've rattled every organisation whether he was closely affiliated or not due to his connections.
Diluc and Kaeya were known to be so close that people often referred to them as twins despite Kaeya being younger and adopted. Diluc having been Mondstadt's youngest knight, he would've been very loved by everyone due to his outgoing nature and passion to protect. Kaeya was considered charming, polite, a sweet young man who stood next to his brother as a helping hand.
The citizens loved them.
And then suddenly, Diluc resigns without a word and leaves without a goodbye. On the same night, Kaeya was reported to be critically wounded, some rumours flying about a cryo vision and burn marks.
A few months later, Kaeya removed the Ragnvindr name from his legal documents, now only going by Alberich. It might not be a formal disownment due to him still being a minor, but it sent the message all the same.
A few months after that, he was promoted to Cavalry Captain and replaced his brother's position in the knights.
Mondstadt watched as Crepus's youngest morph into a silver-tongued charmer, walls so high that people forgot the person behind it. Most of the folks chalked it up to aging and growing up into his own person, though a select few stared at Kaeya in pity. A boy who lost it all. A polite and reserved young knight turned charmer to cope.
The entire structure of Mondstadt was shaken in a single night with no time to recover due to disasters after disasters.
One death of a prominent figure was bad enough, especially with his contributions to the core of their economy and the knights, but both his sons as well? The ENTIRE Ragnvindr family, at least legally, down in one night?
Those two years were shaky at best, brittle at worst. Godd I wish we knew more.
