If Viserys intended Rhaenyra to succeed him successfully, comparing his actions vs. Daeron II show either a falsehood/mischaracterization, or god forbid, actual poor character consistency by George himself.

Daeron II was king of the Seven Kingdoms during The Hedge Knight, the first Dunk and Egg book. Looking into how a stable Targaryen monarch secures his succession, it seems very obvious that after Lyonel Strong, hand of the king, meets his unfortunate demise Rhaenyra should have been the next Hand.

Making your heir Hand of the King makes sense on so many levels, it almost justifies a position that has no true corollary in reality. It's too much power for a monarch to cede in a true unbounded monarchy, essentially creating another monarch and handing them all of your power and authority.

Anyways, making your heir Hand of the King allows you to observe them wield power and authority and how it affects them. The position is a vehicle for you to impart lessons and wisdom on your heir as they grapple with the affairs of state, the competing personalities, the royal household etc. It facilitates a learning curve so everything isn't piled onto their shoulders on day 1. It allows the heir to become comfortable with the various mechanics and appendages of state, teaches them to run the Small Council, and how to manage their families. Important for Viserys I, it would show them how to run, and not be run, by their own hand in the future. It lets the state and the populace begin to get comfortable with the future monarch, see what rule under them would entail, and if any hard lines exist allows time for the system to adapt.

As Viserys I was incapacitated by his illness, he could abdicate due to health reasons and allow Rhaenyra to run things, which would effectively eliminate the chance of civil war on his death. Remember, the only reason he ever became King was for the exact reason of preventing a civil war of succession due to a female being the only living direct blood heir.

So here is the narrative inconsistency/issue, why did Viserys not do this?

If he disliked/mistrusted Rhaenyra and didn't trust her with power, he would have named a different heir. The realm was under no great threat or turmoil, a Hand to save the Kingdom was completely unnecessary. He had no great trust of Otto, having dismissed him already.

By his characterization, Viserys had no great love of power. It appears he viewed the position as a burden and a source of unhappiness. He does not revel in his Targaryen heritage like his brother, doesn't seek conflict, doesn't indulge excessive vices.

Unless Viserys I was actively seeking civil war upon his death, his actions and choices violate the internal logic of A Song of Ice and Fire. He is taking actions and making choices not supported by his characterization or the setting. Am I misunderstanding something?