Trading down for Bamba and Doncic (if they can net another top 6 pick so two top 6 picks in total) would not be such a bad idea.
First let me say I'm happy with Ayton at #1.
I agree with others the above type trade is difficult and would require some luck. It would require two separate trades.
It starts with the Suns finding a team to trade down to say #3 or #4 so they can draft i.e., Bamba or Jackson. The Suns would have to pick up significant assets in the trade to make it worthwhile. Then the Suns would need to bundle those assets with #16 and a couple of more first round picks to get a team to consider letting them move back into the top 7 or so... maybe slightly later.
Additionally a player the Suns like would have to slide a bit.
A simple way to look at it, the Suns would trade down for Jackson or Bamba, then use a ton of assets to throw at another lottery team drafting early if a player they like slides.
Maybe a player the Suns like doesn't slide so they would have to be happy with whoever they draft as much as Ayton. However, they could use those additional assets to overwhelm a team with a trade offer for a player this summer.