When 9.2 comes - Patch release and Raid

Patch 9.2 comes out on February 22 for US and 23 for EU. 

Check the dates here when season 2 pvp and M+ ends. 

https://worldofwarcraft.com/en-us/news/23761715/shadowlands-the-eternitys-end-content-update-goes-live-february-22

When does Sepulcher of the First Ones RAID unlock/release?

It is not stated yet by Blizzard but these are the dates on how it should look based on previous patches. 

Normal and Heroic  1st March US / 2nd March EU (First 8 bosses)
8th March US / 9th Mach EU (Last 3 bosses unlocks)
Mythic  8th March US / 9th Mach EU

 

Raid finder  
Wing 1 8th March US / 9th March EU
Wing 2 22nd March US / 23rd March EU
Wing 3 5th April US / 6th April EU
Wing 4 19th April US / 20th April EU 

10 Feb 2022