Figure Eight knot is tied almost identically to an overhand knot, except you "turn left" instead of "turning right" into the loop. Under no circumstances is a figure eight knot harder to tie than an overhand knot.

https://www.101knots.com/wp-content/uploads/2016/11/How-to-T...

In fact, I've practiced the figure 8 knot so much, that it takes more effort for me to do an overhand knot these days. Figure 8 is really easy.

Just as the "Granny Knot" is a mistaken square knot / reef knot... the "Overhand Knot" is basically a mistaken figure-8 knot. Just turn the other way, and the knot will be far, far stronger.

They're pretty identical in terms of ease of tying, it's just one extra flick of your wrist before you pass the working end back through.

I think the difference in speed would be measured in milliseconds. You'd need a slow-motion camera to spot see any difference at all.

The double overhand knot is better than a figure-eight when used as a stop-knot at the end of a rope that you want to prevent running out through a block or clutch, because it's easier to untie after being jammed.