I picked other. Here's what I'd do:
During the opening credits, Daily Planet clippings would be shown. They'd cover a few Superman events, such as: Superman's debut; a few of Superman averting disasters; Lex Luthor as president; Lex Luthor impeached, convicted and imprisoned; Death of Superman; Superman returns; Lois & Clark wedding announcement; birth announcement for Jon; and a recent one with Superman & the Superboys (Conner and Jon).
We'd open at Ma & Pa Kent's farmhouse with the whole family having dinner. Jon's about the same age he was before they aged him up recently.. Clark hears something & leaves during dessert after hearing something requiring Superman. Show the event briefly, then Lois & Clark at work at the Daily Planet. Lois is the assistant editor to Perry, but still writes. Pepper in each calling each other Smallville & Metropolis while they are mentioning President John Henry Irons. That'd set the stage. Clark would take off to investigate reports of aliens. He'd find a small, well armed group underground, switch to the red & blue, take them down, and put them in DEO custody. Have Superman on his way home when he hears reports of multiple incursions by hostile alien forces.
Second Act
We'd launch into Superman taking on the invaders in Metropolis. His hands are full with them, but he's handling it with while Jon is shown a bit rescuing endangered civilians & helping with evacuation. Name drop Conner's team & Steel fighting combating one of the groups (DC?), and some other heroes would get named dropped. Maybe the Outsiders in Gotham, Diana in Athens, the Titans on the West Coast, John Stewart & another Earth GL in the midwest, Shazam in Fawcett, Global Guardians in Europe, Rocket Reds & Great Ten in Moscow & Beijing, etc. No need to show any of them yet. Just planting seeds for ideas that catch on. He'd just about be in the mopping up stage when their backup arrives in the form of Mongul.
Act 3
Superman manages to get Mongul out of the city to minimize further collateral damage, and the big fight happens. Initially, Mongul has the upper hand, but Superman eventually prevails. Just as he's got Mongul on the ground and nearly beaten, and both of them are out of breath. Mongul says something enigmatic like "this isn't over", taps a commlink, and is teleported out. Cut to the end: Daily Planet news room discussion of the aliens. Some were willing soldiers, others were conscripted and forced to fight. Those are requesting asylum. Maybe mention public opinion being divided, but John Stewart is contacting his Corps to verify the claims of the asylum seekers & seek intel on the invaders. If verified, POTUS is expected to grant temporary asylum while awaiting their transport back to their worlds. We'd end as we started: Sunday dinner at the Kent's farmhouse. No dialogue, just music & family. Roll the credit.
Mid-credit stinger: Mongul on Warworld, insolently admitting failure to his superior. We don't see him, but he has a robotic voice.
Setups up a trilogy. I'm thinking movie two is largely Superman in the Fortress. Black Mercy on his chest, Mongul standing by & gloating, then most of the movie is the Black Mercy dream/nightmare. During it, we meet Kara. It all turns bad, Superman comes out of it in a rage, and he viciously beats down Mongul. Destroys his commlink, knocks him out, and takes him into custody. Uses his own communicator to contact John Stewart, and the movie ends with A couple of GLs seen from afar rising from the Fortress with Mongul captive, and Superman heading to Smallville. Bookend the movie with Sunday dinner at the Kent farmhouse.
Mid-credit stinger: The DEO contacts Superman to inform him of a crashed alien ship. A blond teen girl was found in it, and no one understands anything she says except she's upset & says Kal-El a lot. We see her, and it is Kara.
Post-credit stinger: Warworld from the exterior, reminiscent of a robotic head. Shift to a throne room/trophy room with what appears to be bottled models of cities. On the throne is robotic Brainiac. Little to know dialogue, just a comment about intervening personally if victory is to be achieved. Close brief shot from inside one of the bottles as its inhabitants look up in terror at Brainiac.
Spin off movie: Supergirl, she's posing as Clark's cousin who is staying with the Kents. Less cosmic, smaller story, adjusting to life on Earth, Smallville High School, and getting the hang of her powers. Some normal villain as opposed to invaders. Bookends with Kara & new friends at a local teen hangout, at the end she happily says she's heading home for Sunday dinner with the whole family!
Third movie: Bigger invasion movie with Brainiac front & center. Wants to capture a few cities from Earth, starting with Metropolis. On-screen secondary appearances during the battle by Steel, Conner, & Kara. Someone in a green & purple suit of armor is seen fighting the invasion too. Jon is happily on rescue, and comments in passing about hoping he can still go hang out with Robin this weekend. Epic battles, victory, & Brainiac defeated but escapes. Warworld, however, is no longer his. Mongul is in charge. Bookend with family dinner, intersperse Daily Planet newsroom scenes during the battle, and mention Luthor escaping from jail.
Mid-Credit scene, Luthor in the armor, swearing revenge.