Edit: I was able to recover my partitions by creating new partition starting and ending with same exact sectors.
I was copying files from my previous installation to my new Gentoo installation. After I was done. I ran wipefs on /dev/nvme0n1 thinking it is my old nvme drive which is connected through usb. I am in disbelief. Lost all of my configuration files. My perfect installation of gentoo. Just gone. How do I never make such mistake again? Thankfully I had backup of passwords file. Rest is gone. I am sad.
Guys, I managed to recover my partitions. I used test disk to write the detected efi partition which was of 500MiB. The gpt partition table backup uses 33 sectors to I created second partition starting from where the previous ended to totalsectors-33. I was able to luksDump the header after this and successfully decrypt and mount my device. I had to grub-install and now my system is up and running. Thank you so much everyone for their help and their kind words.