This is, i think, where the Iranians have some strategic wriggle room.
Nuclear weapons are fundamentally political devices rather than military. As the old saying goes, nobody wins a nuclear war - and everyone realises this. Even the most sure-of-heaven religious fanatic (or whatever denomination you care to name) is none too keen on the idea of a terrible rotting death from radiation poisoning while everything and everyone you ever loved burns around you.
A nuclear weapon is a weapon to be held back as a threat, not (except in unthinkable extremis) a weapon to be actually used. They exist to make people treat you with kid gloves.
As such, my personal opinion is that right now Iran probably doesn’t need their nuclear weapon to be militarily, practically deliverable. They just need it to exist, and provably work. If you can make the stuff blow up, you’re most of the way there from a deterrent point of view. Would Israel have bombed iran quite so casually and cheerfully over the last month if Iran had previously test-detonated a nuke? I suspect the answer is no. While a missile is the classic delivery system for a nuclear weapon, it;s certainly not the only one. Hiding one in a cargo ship and sailing it into a port is an obvious possibility for delivery. Tiny locked-down Israel would be a very difficult target for such an attack - but America with its hundreds of ports and vast trade volumes would be a much easier one. It is a low-percentage play that could fail many different ways if you ever have to practically militarily do it, but if you have the explosive device, then it’s still an option that’s open to you - and your enemies know that and have to account for that when they are choosing their political strategies.
To do this, your weaponisation requirements are much simpler. You can use a heavier, less efficient, easier to build design. You can detonate your test device underground or on a tower like Trinity, no rockets or miniaturisation etc required. And you can even threaten to deliver a similar clunky weapon via non-conventional means. A lower-percentage-of-success nuclear deterrent is still a nuclear deterrent - and fundamentally, that’s what nuclear weapons are for.
If (and you’d know more about this than me) the Iranians are likely to have access to enough HEU to assemble SOME kind of explosive device, then that might be the path they take. Set off a test detonation, then announce that in line with other nuclear nations’ policies, any strike - even conventional - against their nuclear capability will be considered a nuclear first strike and will trigger a response in kind. If you have a deterrent, no matter how imperfect, you still get treated with more circumspection - just ask North Korea or Russia. That MIGHT give them enough breathing space to actually rebuild their busted capabilities and build devices that might actually be conventionally deliverable, so they can become a practical nuclear power in the modern sense.
US/Israel vs Iran is militarily enormously lopsided. Iran just can’t stand up in that company. So I think that assuming Iran will attempt to operate a conventional nuclear strategy is a mistake. We have to think about what asymmetric nuclear strategies might be available to them.