I've tried to recreate one of the Ducky3D Text Tool video myself and I'm stuck in this situation where the points of the cube were too many for some of the alphabets that have curved side like this.
Here are the nodes
I tried to realize the instance but doesn't work. maybe my workflow was wrong. please let me know if you have a better solution for this.
If I did not miss something in the nodetree, there are only two outputs which produce curves: the String to Curves node and the Mesh to Curve node. Resampling the curves from the Mesh to Curve node will not work, because thanks to making them a mesh and extruding them, most of the edges will all be individual splines of just 2 or 3 vertices.
So the only chance to place a Resample Curve node will be between the String to Curves and Fill Curve nodes. However since you can only resample by Length or Count the result might not be great (Evaluated does not help either, this is only needed for Bézier curves with subdivisions).
Unfortunately there is no Dissolve node in GN (yet?) like the Limited Dissolve function in Edit Mode where you can add a Threshold angle below which vertices and edges can be dissolved. Which means, this answer only gives you advice on how and where to resample the curve, but I guess it will not give you the desired result.
There is kind of a workaround, but it requires you to use a regular text object instead of creating the text inside Geometry Nodes.
When using a text object, you can add a Decimate modifier to it. There you can either in Collapse mode decide the percentage of how many points you want to keep by adding a Ratio < 1, or you can use the Planar mode where you can set an Angle Limit just like when you use Limited Dissolve.
But the good thing is, this is still fully procedural. You can still change the text and change the Angle Limit whenever you like. If you now add a Geometry Nodes modifier, you can basically use the same nodetree like before, only that the String to Curves and Fill Curve node are no longer needed and you can directly plug the Group Input > Geometry into the nodes where you originally plugged the output of the Fill Curve node.
So here is a regular text object with GN nodetree to instance some icospheres on the control points just "as is", there are quite a lot of points in the curved parts:
And here the same text object but with a Decimate modifier before the Geometry Nodes modifier, the mode set to Planar with an Angle Limit of 12°:
And for the original nodetree, it would change the setup like this:
