Hi , Thank you very much for the warm welcome 
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It seems there are two mirror lists in the pacman.d/ directory
1 mirrorlist.
2.endeavouros-mirrorlist.
I am unsure which one to update but since the only bold letters are Arch I think it’s the first one .
So I ran reflector and selected only two countries Germany and US based on rate and https . So there are 9 German and 1 Us server links in the mirrorlist.
After that ran eos-reflector from the welcome script dialogue , which updated the list at the end but just to be safe un-commented 3 servers listed under Germany at the beginning.
Followed by yay / sudo pacman -Sy . And it still gives the same error.
https://imgur.com/t4dhi4X.png.
Extra steps added India mirrors from the forums , well it updates the mirrorlist , but system update gives same error.
Tried different combination of countries both in mirrorlist and endv-mirrorlist , with same error.
On a side note tried installing Arch (heh) from scratch and funnily enough ‘pacstrap base linux’ gave the same pgp key error. It seems problem truly lies in Arch-keyring .I am not sure what could be the problem here or how to proceed further .