How to loop over different subdirectories and fetch different files using bash

Question

I'm trying to loop over different subdirectories and fetch the files.but getting "no such file found exception"

For example : structure is like tmp/app1/app1a/some.yml and tmp/app1/app2a/some.txt tmp/app1/app2a/dirr

Ex2

tmp/app2/app2a/some.txt tmp/app2/app2a/dirrr tmp/app3/some.txt

My goal is to fetch all the files which are having "debug" String.

For this I started initially to fetch a file from subdirectories.

Cd ~

Cd /home/dir

ls | xargs -L 1 -d '\n' | while read a 

do 
 cd $a

ls | xargs -L 1 -d '\n' | while read b

do 
 cd $b

ls | xargs -L 1 -d '\n' | while read c

do

 temp='cat $c | egrep "debug|DEBUG" | awk '{print $1}''

 echo $temp >> /dirr/example.txt

     done
   done
 done

This is just an example where I'm trying to find the correct loop.

Please ignore typo errors in code.

Using bash to code.