Name change process with two names

Respected Experts, My name is written in all my important documents like aadhar & educational certificates as " S V N Rishitha Pinnammaneni". Where as my name is written in Passport as "Sai Venkata Naga Rishitha Pinnammaneni" which is nothing but a full form of my abbreviated name, as passport won't take names with abbreviations. So, now I want to change my name legally to - "Sai Rishitha Pinnammaneni". It helps me to maintain consistency and keeps my name short and convenient. Now I should go through all the processes of affidavit, newspaper publishing & Gazette . Changing name in educational certificates is a tedious task so i just plan on showing the legal name change proof attached in the future scenarios. Now, Please advice me experts what old name should I use in the affidavit, newspapers & Gazette. CASE 1:- If I use my full name as in passport, it might lead to confusion in the future as all my important documents are in abbreviated name. I plan to do MS abroad, so if I use full name I'm worried they will ask about why my old name in the affidavit/Gazette is not matching with my certificates name. CASE 2 :- If I use my abbreviated name, I'm worried that passport office won't accept it. What if they disagree to change my name as my old name in Gazette will be my abbreviated name but not my old passport full name . CASE 3 :- Is it possible to mention both my names in the affidavit, newspapers & Gazette? Stating like " I, S V N Rishitha Pinnammaneni also known as Sai Venkata Naga Rishitha Pinnammaneni going to change my name to Sai Rishitha Pinnammaneni " Is it okay if I mention my both names in affidavit newspapers and Gazette? Will there be enough space to mention my both names? Please help me on this experts, What old name will be legal & lawful? What old name should I use in my affidavit, newspapers & Gazette? My full name or abbreviated name Or both??