I still havent made up my mind about it. There are some games like the headmaster that are all grind, very little content per character. Some games that are straight to the point like mystic manor, and some games that are a good mix of both like harem hotel *sigh*. I like all the games I listed here pretty much the same amount give or take a few points, so I really cant say. Think it has to do with a good mesh of all elements, not just the gameplay.
Grind when it's like, sandbox tedium of slowly making money repeating the same tasks, no, that sucks. But slow build where you slowly build a relationship / learn more about the characters is great.
Depends what you mean. I HATE grinding but stories that rush straight into the sex are also unsatisfying. Having things nicely paced with some story buildup to each LI is the best.
My favorite style is visual novels with moderate branching, and I prefer kinetic or highly branching visual novels over sandbox style. Especially if they take it slow and have a proper story. Sandbox is OK, so long as it's not grindy. However, I tolerate grind so long as it's worth it relative to the quality of the plot and/or the sex scenes. These are the grindiest games that I have tolerated so far:
Harem Hotel (started in 2018; ongoing) has a great plot and fantastic world building as well as plenty of good sex scenes. I might have given up anyway, but after making myself rich with a money cheat I find I can just barely tolerate the grind required to advance the story.
The Headmaster (started in 2019; ongoing) has less content and a spanking obsession that I don't share, but it's so great overall that I even continued playing when a bug made it excessively grinding. However, for now I don't continue playing but just unlock the gallery when a new installment comes out.
Club Detention (started in 2022; ongoing) is also great, but last time I played it there were severe issues with the sandbox. It got more and more grindy towards the end. It looked as if there was a bit more content, but I am not sure if that was even the case. In any case I got burned, and before I actually play this borderline case again, I will wait for a few more updates and then first inspect the new content by unpacking it with unrpa.