Spoilers. When you see an detached eye spying on the main character, it is up near ceiling. A spider crawls onto the eye. It is the focus of the shot and very triggering.
somewhat, Maria is implyed to have given a sexual ‘favour’ to a boss when employed as a cleaner but nothing is shown on screen and age is not mentioned
Just the aftermath - a character is cleaning up a gross puddle of what looks like v-mit in a bathroom (early in the section titled THE VIRGIL - sorry for no timestamp)
No significant flashing lights. There is a scene with some flames against a dim background, and once a character fires a shotgun to partially light up a room, but no strobing or major flickering. The end credits are a series of drawings that do kind of flash by, but they're nothing to worry about missing.