Vault 69

Ah yes, the obvious choice for one such as yourself. Not much is canonically known about Vault 69, other than one line in the Fallout Bible describing the experiment that was to be conducted there: 'Of the one thousand people who entered, there was only one man.'

It is unknown where this Vault was located, or whether it was ultimately a 'success' or not, but being the only man in a Vault filled with women offers plenty of interesting possibilities, especially given that you can use your new powers to alter the situation however you desire.

The tweak to make sure every woman in the Vault is 18 or older and very attractive is pretty much a given here, but the two obvious extremes you could put yourself into are worth considering as well. Perhaps being the only male resulted in you becoming the ultimate authority in Vault 69, using sex and your status as the only means of reproducing in the Vault to get whatever you want from the other residents, even the Overseer herself... assuming you weren't appointed the Overseer to begin with, of course. Or if you prefer a more submissive role, perhaps the 999 women in the Vault **** you into a role of sexual servitude to the other members of the Vault, with varying levels of compassion for your situation among them.

Of course, a being with reality altering capabilities as powerful as yours isn't limited to just those two options. You could put yourself anywhere in between on the power spectrum. Perhaps different residents have different opinions on what your role in the Vault should be, and Vault 69 is divided into multiple factions of women that you have to navigate between. Maybe they have all decided to just treat you the same as any other member of the Vault in spite of the situation, other than being a lot more forward with sexual advances since you're the only man around. Or maybe you're actually curious about how the experiment would go without any meddling from you, and want to insert yourself into the Vault immediately after the door seals shut and everyone else is only just starting to figure out the 'placement error'. And if you're really crazy, maybe you instead want to experience things as one of the 999 women rather than the one man.

The possibilities are limited only by your imagination and willingness to carry them out. Just remember, the Vaults were never meant to save anyone, so don't feel too bad if not everyone in Vault 69 ends up happy with how things turn out. After all, there are far worse Vaults they could have ended up in.