It's fairly easy for me to know what it's like to have royalty around because I live in a constitutional monarchy under Queen Elizabeth II. But of course, Monarchy is different in my comic because it's more like a role a person can take on with a magic sword that mostly involves being leader of the knights (but does come with a sweet castle and some political clout).
I find a lot of webcomic depictions of Royalty tend to be a bit....off? Like the most common issue is that the royals never seem to do anything. They just hang around all day wearing fancy formal clothes as if a person with supreme executive power supposedly appointed by God wouldn't be in demand. Being king or queen is effectively like being the CEO of a country; you have to make appearances at events, go to meetings, be there to formalise decisions etc... but there's also a military aspect to it. The monarch of England is the head of state, the head of the church and the head of the armed forces, and it's traditional for members of the royal bloodline to serve in the armed forces when they're young. As a teenage princess, Elizabeth II served in the Auxiliary services during WW2 as a driver and mechanic, for example.
Part of the reason Queen Liz has maintained pretty solid popularity in this country is that she works hard and doesn't abuse her power. Technically she has the power to refuse to let a democratically elected prime minister take office, or to veto any law being passed that she doesn't like, but she's never used these. She's very stoic and reliable, and only in her 90s has started passing off duties of appearing at state events to her kids and grandkids.
So yeah... these airheaded royals who just spend all their time at parties but are still popular with the public somehow feel very unrealistic, and in reality, upper and middle class people concerned for the country's future would almost certainly start manoeuvring to remove such a person, and galvanise the peasants to join in if they needed to (most revolutions are not started by peasants... side eyes at how Americans talk about their revolutionary war). France lost its monarchy because their rulers did stupid crap like dissolving parliament and spending all their time having extravagant parties in a huge party house instead of actually acting as head of state. You have to act like the head or you lose your.... yeah.
The other thing often missing when people depict a european style monarchy without proper research, is the weight of history. The royal family is steeped in ancient traditions, heirlooms and symbolism to the point there are literal "royalty experts" that give commentary on the context during events like the royal wedding on TV. They have all sorts of rules about what are "traditional names" for kids who are in line for the throne, usually Charles, George, Henry or Edward, there's loads of symbolism to the different jewellery the Queen owns, who it used to belong to or who is was a gift from, and there are very old rules about how to properly address people (for example, you must always call the queen "ma'am" and never turn your back to her).
So when depicting a King and his knights in Errant, I look to how the royal family is treated in modern day Britain. Wills & Kate are kind of like celebrities, like a rockstar or actor, but there's also this element of fairytale or ancient grandeur to them and these ancient traditions too, and this awkward mix because there's politics in there too. Urien is aiming to be the "cool, modern monarch", but he also plays into that "handsome prince" fairytale image... not totally unlike Prince Harry.