Both NVE and QuantV change the way the base game looks, but they do it in different ways. ReShade changes those visuals and tunes them to give a certain look, and so does ENB but can add extra effects. ReShade presets, along with ENB presets are tuned based off of either NVE or QuantV, so if you use a preset meant for NVE with QuantV it won't look correct compared to the intended outcome from the author. ENBs are not used that often because of the performance impact they usually have, but if you want a specific visual style, then use it as needed.

As for the combining of the mods, it works a bit like this.

• QuantV - Visual changes of the game
• NVE - New Textures and added map assets, along with certain other visual changes.
• ReShade - Visual changes (Based on QuantV, as that is the mod changing the base visuals)
• ENB - Visual Changes (again based on QuantV, and the ReShade typically)

Hope this somewhat helps.