Yeah, Vgs(th) is 3V worst-case. That's the specification for 1mA of current flow Ids, which is near useless (note: the Arduino has traditionally been able to supply 20mA+, so a 1mA Ids current at 3V is completely pointless). "th" is Threshold after all, its not when the MOSFET is usable, its when it "starts to turn on".
Figure 2 on page 5 gives you an idea of the voltages you're supposed to use. Optimal usage of the 2N7000 requires 10V Vgs (for 1.5A or more), but 5V is sufficient for ~800mA bursts. And I expect 800mA to be enough for most beginner uses.
https://rocelec.widen.net/view/pdf/orqxwkxkq1/ONSM-S-A000354...
Figure 2 on page 5 gives you an idea of the voltages you're supposed to use. Optimal usage of the 2N7000 requires 10V Vgs (for 1.5A or more), but 5V is sufficient for ~800mA bursts. And I expect 800mA to be enough for most beginner uses.