Harem Hotel is an adult visual novel, what you're describing as a grind is reading through their stories.
As it tells you at the beginning of the game through tips, which you seem to have ignored, stats do not progress the story. They unlock side content.
You also seemed to have rushed to the sex content, which is not this game's focus, and ignored all of the ways to gain money. Such as through deliveries, the bar, the garden, and so on. This game is quite easy if you read what's going on, and holds your hand so that even someone 4 blunts in can easily progress.
Maria doesn't want to be creampied early in the story. She doesn't hate you, you just don't seem to be reading what's going on. If you want a quick nut, pornhub is available.
And yes, that's correct, you typically cannot take women out on dates at 2AM, even in the real world. Cafes and bowling alleys are typically closed during these times. But their legs may not be.