>>91123625Aside from the aforementioned Lah is your sister and La+ recruits you into HoloX (which frankly are a supermajority of where Laplus romance would start), you kind of have slim pickings for where to start.
1. She's an escaped military experiment ala that mecha idea but sans daughter implications. So something like you run into an escaped Laplus on the outskirts of town and do a stranger things with her while slowly falling in love together.
2. Your chuunibyou classmate is actually something more? Highschool/middle school setting, you're one of Laplus' few friends and get into supernatural shenanigans with a girl who does actually have sealed power.
3. The shared chuuni origin childhood friend. If you remember that one greentext about playing with a young Laplus surrounded by Lava (Red Legos) something akin to that but extended into a long form romance.
4. Fuck it fantasy setting, spin a tale of a sealed demon lord and her elite four with a hero chosen by the heavens rising to oppose her... And the forbidden romance that somehow springs between two traveling companions unaware of their fated destiny to fight for the fate of the world.