Finding difference in values in the same row, different column within a Matrix

I've been stumped with the solution to this problem. I have a matrix table that produces this output.

The desired output is something like this ( figures are made up) 

I want to display the difference in ranking and CT% (Market Share) between the value in a row and the following value in the next column within the row. There are no dates within the source data the output is a string of the respective period.  

Within the data, you have Years and Quarters within the period field represented below:

example for 2021: 21Q1, 21Q2, 21Q3, 21Q4, 21Y

I wish not to be restricted to QoQ and YoY, for example, if a user picks Q4 2022 and Q1 2020 I would like to be able to show the difference between the selected values.

Many thanks,