Uncapped vs. Capped FPS for Competitive Gaming

[numanumahey]

Uncapped:

I am in a little bit of a predicament when it comes to deciding between capping my frames or not. Using RTSS and MSI I have come to the conclusion that leaving frames uncapped (g-sync and v-sync off) in Fortnite leads to ~2ms less frame time (4ms to 2ms) which is actually a noticeable difference for me. The trouble with leaving frames uncapped is that my FPS are not very consistent and they range from 200 - 500. I think the average was around 350 with lows of 190 FPS. My first question is what are the cons of having such a variable FPS throughout the game? I suspect it has an effect on aim because when I leave my frames uncapped my aim might feel more sensitive or harder to control (i'm not 100% sure yet, it could've just been an off day). The reduced latency feels really nice but I am unsure if this is the right approach due to the inconsistent FPS.

Capped:

Capping my frames at 237 FPS and turning g-sync on leads to much more consistent frames around an average of 237 with lows of 200 (or lower) depending on the player density. The frame time in this scenario is around 4.2 ms which does not feel as responsive as before but the game does feel more consistent. Does frame rate consistency have an effect on perceived sensitivity, aim, or mouse polling?

I am not worried about tearing or the way the game looks. I would leave my frames uncapped if it weren't for the lingering suspicion that such inconsistent frames lead to inconsistent aim as well. I plan to run a benchmark throughout an entire gaming session and compare these two scenarios. Perhaps I may find a nice middle ground like capping my frames at 300 FPS while leaving g-sync off.

Any insight or suggestions would be really appreciated.