You don’t know which country, its random.
You cannot leave this island, you cannot end your life, you cannot abdicate your position.
Your country is immune from military attacks for 10 years, its literally impossible. There’s a magic force field protecting the entire island and the entire airspace up to 41,000 ft (max civillian flight level) and 12 nautical miles sorrounding the island. Enemy military are unable to enter.
You cannot get kidnapped or killed or like fall into a coma, or anything of the sort, you have plot armor for these 10 years. Any assassination attempts will magically fail.
Your population does not have plot armor they can die.
The enemy can send spies.
You get to choose the location of your island at the start. Things spawn in, and has a random amount of development of an average developing country, history, culture is randomly filled in and backdated. Everyone speaks your most fluent language and is literate.
You have zero nukes.
The easy answer? Choose somewhere with uranium deposits, and bootstrap a nuclear program. 10 years should be enough given the 100% literacy rate implying a pretty robust education base already.
Other than that, a pop of 30M over 900000km2 is pretty low density for a country so I’d pick an island with a large internal barren desert and huddle people up in 3 or 4 isolated shelters and then force the enemy through a long tough and brutal desert attrition war until they give up or we die. And that’s after mining the ocean around the island and fortifying the coast.
That should make the effort of attacking vastly outweigh the benefits leading to a long term pyrrhic victory.
Assuming of course that I can’t build a strong enough military in those 10 years. 30M pop with high literacy rate and a pretty good cohesive culture (speaking the same language) should make militarising pretty easy too and propel us into a top 10 army on its own.
No I mean you don’t get to pick what resources are on the island.
You pick a location in a world exactly like this one, except with an additional randomly generated island at a random place in the ocean of your choosing. Like you pick a spot in the ocean big enough for this island to spawn, then the island is spawn into the world and you spawn in as their dictator. Resources are random. You may or may not have Uranium. (Do Islands even have Uranium/Plutonium?)
I mean, I’m pretty sure you can find uranium in all kinds of places.
Either way I get that it’s not in the spirit of the question, so I added a “real” answer too ;) The plan wouldn’t really change much whether there’s an inland desert or not too, though the island certainly should end up big enough to possibly have one.