Dark mode
After a long search and a lot of trying, it turned out this app has all the features I was looking for (except for the week numbers being visible). It does seem to lag behind updates often (blank calendar after update). I use the entire phone in dark mode, including the calendar on my home screen. After the iOS 18 update, it suddenly had a white display. A little fiddling with the settings brought it back to dark mode, but after one night, it unfortunately returned to white…?? I hope this can be set back to dark mode soon.