Playback processing for Data Driven tests slows down the longer it runs.

I don't think complexity of your test would slow you down.

b'cos any computer operation those decision making process such as "if then else" are much faster.

first I would be looking at how you log your results. are you saving big pictures on your log file ?  dose it save to external hard disc?

do you have enough RAM in your test machine? do you use external data base?

do you open lot of windows and screens one after other? 

dose your app is working on back ground in each of these test operations?

did you check memory , processor usage in Task manager of test machine? 

what configurations you have ? in terms of XL, Testcomplete, App, servers, DB.etc.

dose you have lot of waiting times in your test?

to improve your speed you can use these tips best-practices-performance-tips

also refer this 

in my testing environment I find slowness when test progresses but it's due to heavy back ground processing in my application. (which it is suppose to ..)

so I close the app, let background finish and re start in particulate intervals.  

Here's a good reference

https://support.smartbear.com/testcomplete/docs/reference/misc/using-wildcards.html

In your first example, if 

textnodeTdxrdesignbaisdropv1x2z12 is really the same object as 13, 14, and 15

then delete three of the lines in the mapping and change the remaining one to textnodeTdxrdesignbaisdropv1x2z*

This will let the object be matched with anything that comes up at the end of that pattern.