Trigger Warning: The title is not meant as flame bait, however it is brutally honest about what you will find in this post. If you are triggered by criticism of Sixth World, you would be better served backing out now. No one would think less of you.
Also, I’ll be upfront. I don’t have any idea of how to “fix” the Edge system without a complete rewrite of the system. Since people tend to be labeled “mean, nasty, stinky, trolls” if they can’t provide suggestions or alternatives along with their criticisms, I do have some ideas of how to improve the system later in the post. They aint fixes by any measure.
I’ve called the Sixth World Edge system as too finicky.
Fickle might be a better word for it. It may not be frequent, but it probably won’t be uncommon for a characters Edge points to change 4+ times a round.
Each time it changes is an opportunity to introduce human error. If it could only change one point at a time, it would mitigate this some.
This makes it difficult to track Edge points accurately. Do note, this isn’t the same as claiming it is difficult to come up with methodologies to track it. That is easy. A D6 and a coin should do you just fine. (More on that a bit later.)
For example, with my play group we have seven people (1 GM and 6 Players). Of those seven, only two are “good” with math. I define that as being able to do simple addition and subtraction with single digit numbers and get accurate results at least 90% of the time.
The rest… Aren’t so good.
It isn’t that the results are “conveniently” in their favor either. They screw themselves at least as often (if not more so) with their errors.
On top of that, technically you have to track 2 numbers each turn. The actual Edge value, and how many points you have gained. I will grant you that the later is a much simpler value to track.
This means if you are a GM that has to supervise your players (either because they are genuinely “not-good” with math, or because they tend to always make errors in their own favor) you can have 10+ Edge pools with Point Gain Limits to track every round.
What makes Sixth World Edge even worse is that digitalizing it doesn’t improve it in anyway. In fact, it makes it worse. 5e’s Situational Modifiers could be a pain in the hoop, sure. That could be fixed with a computer script (ask me how I know.

). Select the situation descriptors, and the script does the math for you.
You can’t do anything like that with Sixth World Edge. Each individual has to track their own Edge and trying to do it digitally actually is more of a pain in the hoop than doing it analog.
That is all I have without scrapping the bottom of the well. On to my suggestions.
Tracking Edge:
Since the most Edge you can have at any one time is 7, use a D6 and a coin.
When you have less than 7 Edge, and haven’t gained any Edge this turn, the top face of the D6 is your Edge points, and place the coin under the D6.
When you gain 1 point of Edge, move the coin to beside the D6 with the “heads” face up.
When you gain your second point, flip the coin to “tails.”
If you have 7 Edge, place the coin on top of the 6 on the D6.
Improving Edge:
Drop the 2 points per turn limit. This removes one of the two numbers having to be tracked, and reduces the points of entry for human error.
Change the max Edge to Edge Attribute + 2. This removes the flattening of the effects of Edge. A character with an Edge Rating of 1 is never able to spend 4+ Edge points at once. It also gives a mechanical advantage to having a 7 Edge.
Where this will likely fall apart:
First, this might resurrect Edge Lords. Being able to “hold” 9 Edge, then spend it, and then regain it… It might be too much.
Second, it might require rebalancing of the Edge Action costs. Off the cuff, I would suggest starting with increasing the cost of 4 and 5 point actions by 1 point, and raising some of the 3 pointers to 4.
Like I said, they ain’t fixes.