Rookie pick value is fluid and dependant on the league.
When we get this close to the draft picks are often broken into tiers and then when traded we have a general idea of who we will take. This often relies on ADP data that can be taken from various sites. One of the issues that comes up is the variation in ADP from site to site. A draft pick does not guarantee the player and this is why earlier picks are more valuable. The earlier the pick, the less risk is taken on in relation to who is available. This is also why players retain value and often increase in value as soon as they are drafted.
This can change from league to league, of course, because of scoring and how the other owners play. If you know more RB’s or QB’s will go early than a normal league, the middle and later picks will have more value. The way to exploit this is finding owners who still devalue the picks, pay what they would be worth in a normal league and instantly gain more value because of the players who will likely fall. It pays to know your league mates. After a couple years in a league you should be able to see how the other owners draft.
Something to keep in mind is the natural flux in rookie pick value. After the season is over they steadily gain value until the rookie draft where they peak. Then future picks hold value while the rookie draft is fresh in the mind and it slow declines. By the start of the season it hold steady for a while then, in my experience, a month or so in they drop in value even more. This is caused by owners who believe they are contending or who will sell the larger future for the more immediate. By being realistic with your team, you can capitalize on this dip. Don’t “rebuild” if you’re not contending, but if there are assets you can move to capitalize on a dip in value, in season is the time to do it.