I guess it's just Lex pulling the strings so he can become king of a nation to develop tech and his own army. Using Supermans good will to get him arrested and turn the public against him. It's just that it's not well written to keep it good. The basic plot had potential but it was squandered by being all over the place when the movie was being put together.
ah ok.
On a surface level that's fine, "lex luthor is smarter than superman and is one step ahead of him the entire time" it's kinda the essence of the conflict between the two I suppose, i've never been a huge superman fan but that's what I pick up from various media.
However I think you missed a few key points in the film that radically alter the plot:
Lex Luthor didn't do any of those things for any of those reasons, his sole motivation the entire film is to kill superman. Everything was just a means to achieve that, he explicitly states as such. Someone earlier mentioned Oil or land or whatever, none of that shit mattered to Lex. he did everything in this movie just to kill superman, he didn't give a shit about land or oil at all, they were just a means to an end.
if you actually think about it for more than 1 second you realize it was the dumbest most convoluted plan in history. not only was it completely unnecessary but it actually was counterproductive. Lex had everything he needed to kill superman within the first 30 seconds of the film, everything that happens in this movie happens because it had to happen for the story to play out, it was poorly written shit plot from a retarded pedophile.
plot points that occur off screen/prior to the start of the movie:
Lex develops a deep hatred for Superman and wants to kill him
Lex creates a pocket dimension as a prison
Lex funds a metahuman group to have supers on his side (the Engineer is one of these, the others aren't even really shown more than 1 split second)
Lex goes to various superman battles to collect superman's blood
Lex clones superman and makes Ultraman, but the clone is retarded
Lex studies Superman's "combat style" of stand still and punch ppl in the face so he can program his ultraman clone with voice prompted action maneuvers to defeat him
Lex kidnaps metamorpho's son, to use as leverage, he has metamorpho create some kryptonite to verify that its real enough and that it will weaken superman/ultraman.
Lex, as an american company in good standing with military contracts, gives weapons to Not_Israel, a staunch US ally
Lex makes a secret plot with Not_Israel to split their neighbor, Poor_Brown_Country in half once they invade using the weapons he gave them (at least, that's the excuse he give's Not_Israel so that they don't question his plan for them to invade and start a war)
Lex dresses up Ultraman as the Riga Hammer, Hero Metahuman of Not_Israel
Not_Israel invades Poor Brown Country, and superman being superman, intervenes to save poor brown people, upsetting US interests and maligning Superman against the US government
Riga Hammer/Ultraman beats the shit out of superman, and superman escapes to the fortress of Solitude.
And that's where the movie begins. All of these plot points are revealed throughout the film since this is a huge amount of back story to just drop in.
And you are lead to believe that this was the plan all along so Lex could break into the Fortress of Solitude and find information on Superman, his weaknesses or something to defeat him, use that information to compromise superman in some way, so that the government would sign off on allowing lex luthor to capture & imprison superman while waiting to try and execute him.
That ends up failing because lex is dumb and keeps metamorpho imprisoned 10 feet from his son, the only leverage he has, and allows superman to talk to metamorpho. Thus superman escapes so in order to draw superman in, he can either have his puppet Not_Israel invade Poor Browns, which 100% would of got superman's attention, but instead he decides to do that AND to allow a dimensional rift to tear apart metropolis and threaten to end all life on earth. To force superman to choose who he is going to save? Ok what if he had flown to Not_israel instead?
All so he can use ultraman to fight and kill superman.
Except he had all of that already at the beginning of the film. Ultraman was beating the shit out of superman. All he had to do was take some of the kryptonite he had metamorpho make and give it to the engineer, and have her murder superman once he crash landed outside the fortress of Solitude.
he didn't need to break in the fortress of solitude, he didn't need any of the information gained, he didn't need permission from the US govt (as far as anyone knew at this time, ultraman was the Riga Hammer, hero of Not_Israel defending his country from an illegal counter invasion from superman and completely untraceable to Lex)
The entire movie happens because Lex Luthor is dumb. Which is typically the opposite of how he is portrayed.
You think its a great plot that is poorly executed.
It's actually a terrible fucking plot that is immaculately executed, it's so frenetic and has so much shit going on that it confuses you, it convinces the average movie going audience that it's a poorly executed good plot when it's the opposite.