CONTEXT: I am exploring a workflow for quick concept modeling. This works as follows: I use the quickcurve addon to draw the outlines of the shapes of the design first. Then the lines (curves) are converted to mesh. Then the open edge loops are connected with eachother with bridge command. (comparable workflow https://www.youtube.com/watch?v=Kvo_F6hC500&ab_channel=JamaJurabaev)

PROBLEM:
I am looking for a way to create slightly cleaner results, as the problem is that simply creating faces or bridging between 2 open edgeloops with different vertex count will result in a lot of triangles which is undesirable as it results in shading artifacts and other problems later down the road.

QUESTION: I am looking for a way to even out the vertex count of two open edge loops (probably unsubdiving rather than adding vertices). This way, using the bridge command will always generate clean results with only quads. I have looked online for a while but am unable to find a way to do it. Any ideas?

Select all the vertices of the curve and use the checker deselect command, dissolve the selected vertices and then select all the vertices again and use the Space command that comes with the loop tools addon (comes with blender by default)

This should sort of cut in half the amount of vertices and still preserve the shape of the curve.

I am not sure if the question is clear enough. Your answer does not guarantee a similar vertex count for the two edges. I made an image to clarify the problem.

What you are asking for is essentially what you aren’t wanting: a reduction to triangles.
Based on your request, I am pressed to see a way to get all quads; something, somewhere, has to reduce to a triangle to get you what you want.
Perhaps there is a fix on this page: https://pixelandpoly.com/img/step-down-guide.png.
edit: put in the right reference.

If there would be a command to unsubdivide the edge per vertice (instead of a factor) then it would be super useful for these kinds of situations. If you have an edge of 7 vertices and another one with 9, you would select the 9 one and unsubdivide it by 2 vertices But I guess such an option is difficult to program.

You can dissolve vertices along an edge loop to lessen the count and subdivide between vertices to add.

For example enable statistics to view vert count, if you have one loop with 5 verts and another with six you can select one of the vertices on the 6 vert loop and dissolve it leaving 5 (hit x then choose dissolve vertices). Or select two adjacent vertices on the 5 vert one and subdivide them to add a sixth (right click then select subdivide).
You can do both of these methods with multiple vertices at once.
You can also dissolve edge loops (x dissolve edge loops) and of course add them with Ctr R.

@ rigoletto: Interesting video. Not sure it answers my question but I learned something new!

@ Dnorman: I understand what you are saying, and I understand how to solve it by subdividing etc. But I am looking a bit more towards a streamlined workflow where these steps are automated with a single command. Repeating these steps for many many lines would be too time consuming for a creative workflow. Thanks for thinking with me!