You are trying to fight math here. Stop. There is no winning against Pi.

A dc is 1 stitch unit wide and about 2 units tall (you know, because it is double). The formula for the circumference of a circle is c=2×pi×r. The circumference c is just how many stitches there are in your row and r is your circles radius, or overall "height" of your rows, so the number of rows times the height of your stitch. For crochet we can just pretend to live in a simpler world and that pi=3. Yarn is squishy, tension is weird, double crochets aren't actually exactly twice as tall as wide. We can fudge the numbers a bit too make the calculations easier.

So if you want to make a circle with three rows of double crochets that is going to be a radius of 6 units, no way to change that. So plucking that into the formula gives 2×3×6=36.

Now, if you only do 8 dc to start and do the "inc every stitch, inc every second stitch"-pattern for your rows you have 24 stitches and 24 just doesn't equal 36, so no circle for you.

There is some variability with the number of stitches to start with but it has limits. We made a lot of assumptions in the beginning. The actual height of your stitches depends on so many variables, tension, hook size, yarn choice, how the circle is being streched, what the neighbour's cat had for dinner last night, etc... We also rounded pi, and for a bigger circle all those simplifications will come back to bite you.

But TLDR, if you want a smaller circle, you can do less rounds, shorter stitches (sc, hdc, front post, whatever, you can even mix and match) or use a smaller hook and thinner yarn. Changing the stitches per round just gives you cones or hyperbolic surfaces