It's a reasonable strategy long term, but we all have to admit how weird and tough to predict the 2021 draft is due to the pandemic. There's a realistic chance that 7 defensemen could be picked by the time the Devils step to the podium with the Islanders pick at #20 or #21 -- Power, Clarke, Hughes, Edvinsson, Lambos, Ceulemans and Heimosalmi.
If this is the case -- even if 6 of these names are gone, which is even more likely -- the "best player available" is very likely to be a forward. Do the Devils pass on a potential game-breaking forward like Rosen, Othmann, Svechkov, Pinelli or Sillinger to grit their teeth and push a lower-ranked defenseman up their draft board? I'm not sure that is the best call.
The reality is that Power, Clarke, Hughes and Edvinsson will be gone by the first 10 or 11 picks.
Lambos can also go in that range, but he can also fall due to a very uninspiring draft-eligible season. He's the ultimate upside/risk player, maybe in the entire 2021 draft. As such, he could go anywhere from the top 10 to the early 20s.
Ceulemans is the most intriguing draft target, since his likely draft range is #15-#25 and the Devils should see themselves drafting in the middle of that range. Also, he's a RD, which a greater need (by far) than LD in the Devils prospect pipeline.
Heimosalmi might be a bit of a stretch at #20 or #21, and although he's also a RD, if he were the best D available with the pick I would hope the Devils would try to trade down 5-9 slots where they could very possibly still get him and also pick up a 2nd round pick.