There is still hope, Trump had an agreement on the table to remove the Iranian enriched Uranium. Maybe someone else can get us back to where we were before he screwed it all up.
Designing a nuclear bomb isn't hard, two random PhD students did that in the 1960s. Machining it is trickier but nothing special with modern tools.
The materials are the only really hard part, and Trump threw away the best chance we've had this century to remove the threat of a nuclear armed Iran. He had a deal on the table to hand them over, then his negotiators walked away and told Trump Iran wasn't going to budge.
I do not see how things can be turned around again but there is still hope that Iran will handover the materials, but everything Trump and Israel does is making it less and less likely.