@hardcore_gamer29 Don't take tension about Engineer. Once he reach your house, Tell him the ping difference between your Friend and You getting in the same server. They'll be able to understand the issue.
If by any chance, They are not able to get the issue? Just tell your friend to send 1 screenshot of test done on that same server and perform it in front of Engineer and after completion, Show him the difference of Ping - Issues. They will be able to understand your issue by that.
If you think your Ping is high at Night-Time and Stable at Morning time, Checkour your IP Address. Sometimes, JIO Change your IP Address (From one server to another server)
This happens sometime automatically and causes High ping issue at different time.
Website to check your IP : whatismyipaddress.com or fast.com or speedtest.net or speed.
cloudflare.com (Remember to check IPv4 not IPv6)
Router restart changes your IP Address, If you restart your router 3 - 4 times, It will give different IP Address and sometime Different IP for different Server.
Example : 1st Restart : 100.100.100.205 2nd : 100.100.100.150 3rd : 200.200.200.120 4th : 100.100.100.123
So, It can be that your 3rd Restart IP gives you better ping than 1st, 2nd and 4th. This happen with me on my BSNL/Airtel Fiber and just a Modem restart fixes my Ping issue in several games.
Either way, Engineer will provide you best solution for what you should do or what they need to fix, You should inform them regarding the recent Fix perform by last Engineer visited your home so that they can be more clarified about the situation you are stuck.