The biggest risk of not now, is that Giannis gets a more serious injury. If someone is offering 4 plus first round picks now and if that someone has an aging team that could break down like Nets did, take that trade asap. Yes, they can wait and see where the first round pick positions are but if he does get injured, the trades and offers will be drastically impacted.
If I was the GM, I would let the teams know, make your best and final offer.
He averages between 60-70 games played a year the past 6 years. I dont see that trend improving as he gets older although a healthy Giannis now is a huge boost for any team on brink of competing for a championship.