i’ve tried the convex hull but that gives me straight lines between the circles.
what i need are arcs that i can adjust in the curvature. at the end it should look
similar to that - a nice clean curve with as few points as possible:

Now this definition takes the same number of circles and text dots for the radius input. The text dots need to be roughly where the arc segment is going to be. Circles can be scaled and dragged.

thank you seghier. this is exactly what i was looking for
one more question:
which component do i need to get a curve with as few points
as possible in the end (see my third picture above)?

when using the control point component i can see that there are too many points on the circle sections.
therefore the curvature seems to be “unclean”.

I tried both BiArc and BzSpan(Bezier Span, white curves). There may be a way around this but I added a ‘VecMag’ slider (yellow group) to “fudge” vector magnitude values for BzSpan. This must be adjusted based on distance between circles, whereas BiArc works well with three sets of curves (blue group, upper left).

Fixed! Instead of slider, used half the Distance between start and end points. Different curve than the piped BiArc but consistent for all three sets of circles.

three control points on the circle sections is just what i wanted.
but there is an offset in the middle of every arc. i wonder if this a break in the curvature or something?
it is still there even if i delete the control points (red) in the middle. no matter i will get that sorted.

new questions:

1. somehow i don’t manage to access the circles to change size and position.
circle component says that there are 4 locally defined values. how can i get in there?

Create your own list of circles any way you like. I modified this model for another thread with a ‘Random Subset’ feature (pink group) to use a subset of the list of circles as a quick way of trying any two circles. Then I found I needed to sort the circle segments differently (teal group).

The “tube” (Pipe) is just cosmetic to show the complete perimeter curve, which is constructed from curve fragments.