I'm all in for no sandbox or minigames. Theoretically they could really add a lot to a game but so far I have never encountered a game where sandbox/minigames made sense, was fun, and wasn't a boring grindfest.
Sandbox != Minigames. You can absolutely have one without the other. I have seen minigames in VN And I have seen sandboxes without minigames.
Sandbox can either go towards having a full game (rather than mere minigame). (ex: skyrim is a full game sandbox).
Or it can be used to split up multiple VNs or multiple kinetic novels that are tangentially related (same MC and same universe).
A lot of VNs make the mistake of having far too many branching options. A sandbox can be used to break apart small groups of girls into discrete mini VNs / KNs. The key is to avoid making them too inter dependent on each other. otherwise you can break things even worse than you would in a VN.
Ideally do not make them completely unrelated, but keep inter-dependence to a minimum and allow opting out.
(eg: if you opt to NOT romantically pursue your mother. it should not block any of the other routes)
There are sandbox games which clearly would have done better as a VN, and vice versa. It really depends on the dev's skills.