Sounds very much like you're "asking for a friend" 😉
Dangerous? Over-valued? Nobody knows anything, it's like Hollywood and making movies. That's for the market to decide, particularly for a high value property that might have unique features that might not be known to your business partner. Obviously the danger is that you don't get an offer at asking but it's not like that's inherently problematic for finding the present market value.
Most realtors will defer to under-valuing a property because it undoubtedly makes it easier to sell and it'll create traffic. This may or may not maximize sales price (this is one reason a realtor is better than an owner for having a strategy on this). Every property is different and market conditions matter. If I was trying to sell something at $500K, for example, I'd probably a lot more flexible on list because there's tons of buyers in that price range (relatively) and I might have better luck trying to encourage a multiple offer scenario.
If, by contrast, I wanted to sell something at $4.2m then maybe I'm more concerned with the perception of exclusivity. Maybe I keep it off MLS, let agents know they can call it a pocket listing. It'll still get out there but I only need one buyer who agrees with me on the value and that's a high enough price that most buyers would be looking for something special (and might feel entitled to it). For example, paying $200 a sq ft premium for a recently remodeled house rather than doing it themselves and saving the money but incurring the hassle.
Historically there's a prejudice against properties on the market for an extended period but I think that's gone away. It might have previously meant the house had problems, the sellers are inflexible (or assholes), realtor incompetent, etc., but there's been so much price/demand volatility (hell, just life volatility) post Covid I really don't think a good buyer's agent declines to show a house because it's been listed for 90 days. As far as pulling it back and then re-listing, who knows? Agents see that, it's not like it's a way to truly re-introduce something "as new".
Is it wise to hold out for a wealthy person? That depends on how urgently the proceeds might be needed.