My apologies if you're already well-versed with these things.

1. In my hours of playing (130-ish), no one seems to wonder why the king whispers random subjects. They usually just assume that the king is privately getting their claim and that assumption is usually the truth, regardless of BD or evil king. Or that the king is asking for last night's results of that particular player without exposing their important role.

2. One of the ways of telling evil dudes you are EK is when:-
a) you get three claims of a class and then later, two of them eventually say in open chat that they are indeed that class, but the third one who claimed that class is silent. Well, just let it slide and hopefully that third guy is an evil who will get the message and tell his friends at night. He might be the NK though :)

b) you ignore inconsistent reports of night activities (e.g: a Princess who gives absolute crap results from Flirting). This one is a guessing game but many veteran EKs can tell crap from genuine logs and will look the other way.

3. You are already aware of the two playstyles of an EK. The most frequent advice would probably be do neither of the extreme. But when I'm EK, I play as if I'm BD almost all the way. Talk/whisper non-stop to show you are engaged.
Divert attention by openly saying "Can I have number ## logs?" or "We need to find the NK"
or "Who did Mystic link last night?" "Who was occupied last night?".
Waste as much of the court's time as possible and divert attention. There's usually someone who takes their time to respond to these questions.

4. I wouldn't tell the Knight to protect me. I would maybe guard the Knight and tell the Knight to guard Prince. And if the prince dies anyway..you got a friend in me. That's just a tactic I thought up but I never tell Knight to guard me even if I'm BD king. Always another player.

In other words, I don't think EK is a bad role at all. It's pretty fun, but takes some experience to play off successfully.
If you don't want to play strategically, just slam a chopper on the Prince when the opportunity rises, either by telling everyone to up someone "Because he didn't claim" and then Decide Fate, or ordering execution at night on the known Prince.
Yeah you'll die soon after, but early Prince death is a kick to the nuts for BD.

They need to do something about the prince meta is what they need to do. You need to convert an enforcer, and get that prince kill, but that is luck.

I would say as king whispers aren't too weird early game in a game where people are claiming to king, but it helps you not to execute your cult / unseen.