This varies by person, and he best person to talk about this is your girlfriend.
With that said, I’d do half what she paid in rent for mortgage (of half the mortgage payment, whichever is smaller), and all other expenses split down the middle. She would pay rent if she lived elsewhere, the way I see it, her contributing to the mortgage is a deeply discounted rent.
This might not work for you, you need to talk. Me and my now husband when we first started setup a joint account, and each sent half of an agreed amount there every month, or as needed. We didn’t make similar incomes, it fluctuated back and forth through the years for both of us. Some people would think it was unfair for us to pay the same. It worked for us, and both of us were happy with the arranjement, it might not be the best option for you.
Play the NYT wordle, mini crossword, connections for the day. I have some small simple games that can be stopped at any time. My most played ones are cake sort, water sort, sudoku and sometimes minesweeper. Also scroll lemmy sometimes, it’s small enough that it doesn’t take long to see everything that is new, so there’s no risk of getting sucked in for long