Max zoom should be 2x

[Hexicube]

Max zoom in amount should be 2x since HD graphics will be 1:1 at that scale, instead of 3.281x that is currently allowable.
Alternatively, 4x would work, but you'd need a massive resolution to even benefit from anything beyond 2x.

Here's some examples of the same area:

3.281x: https://i.imgur.com/XMOzx9J.png
2.208x (next after 2x): https://i.imgur.com/NweYnyW.png
2x (note the sharpness): https://i.imgur.com/kf8kzIi.png
1.811x (last before 2x): https://i.imgur.com/Q2KhsJU.png