Just had my 14 team IDP draft earlier today. HSG hit the nail on the head, it all depends on scoring. In mine - We start 1 LB, 1 DE, 1 DB, and then 1 Flex IDP which is always an LB for me since tackles are the most prevalent scoring option. In our league pretty much everything is 1 point (tackles, sacks, passes defensed, interceptions, fumble forced). This means in my league on average, an IDP player scores somewhere between 5 and 10 points, which is about what a kicker scores. So I treat them like kickers and I wait until the end to draft them. While everyone else starts diving in for Darius Leonard, Kahlil Mack and Aaron Donald in round 8 or 9, I"m filling up my bench with pretty much my choice of RB4s or WR3s, and I end up with Corey Littleton or Bobby Wagner in round 14 while everyone else is now going for kickers and backup QB.
What makes your week is when your IDP guy gets an int or picks up a fumble (or strip-sacks) and returns it for a TD, but that's impossible to predict.
To the OP: Take a look at 2019 scoring of IDP's in your league page, and get an idea of how they score. Since you only need to start one, look at the top 15ish or so from last year. If 12 points separates them total, then no sense in reaching for one. If the scoring is more heavily weighted, then adjust accordingly. If this is a longtime league, there will come a moment when a run happens, and probably within 2 rounds everyone will have their one guy. If the scoring is fairly even and the top ~15 are all close, then let the run go by you and fill at the end.