You don't need VBA for this.

In the example below, the formula in B2 stands in for your arbitarily-cnmplicated calculation chain. Note the formula in B4.

Select A4:B12, Data > What If Analysis, Column input cell: A2

That's it.

Row\Col
A
B
C
1
Input
Output
2
26.998
528.892
 B2: =A2^2 - 200
3
4
Inputs
528.892
 B4: =B2
5
29.234
654.627
6
29.456
667.656
7
28.723
625.011
8
26.998
528.892
9
27.906
578.745
10
27.253
542.726
11
28.123
590.903
12
29.717
683.100