I often play a VN alongside with a game of another genre (particularly if the VN is on the PC, since that means it will take me longer, while when it is on Switch I often play it alonte until I finish). But in my case I don't find difficult to re-enter a stopped VN. Even though I could have the sensation to have forgotten everything, as soon as I read some lineas I start to remember (my memory works this way also in other fields, not only for games).
In the meantime, I started The Fruit of Grisaia. I am currently in the common route (in July, so I think I am near the first character route). It is quite long, I have already played it for more than 10 hours, and particularly episodic, it is clearly not the VN I would suggest to someone as their first VN. However, all the five main girls are amazing and all the episodes convey some feelings (fun most of all, but some moire serious theme which I suppose will become relevant later have already been touch, like death). Now I am looking forward to playing the five routes, I think I will follow the natural order in which they are presented: Makina, Amane, Sachi, Chiruchiru Michiru, Yumiko. I read online so many different suggestions about the route orders, so I think I will just go for the traditional one.