CLIMAX CRISIS Extended to 20 minutes+
One of the BGM from Chakuma 2022 event.
This is the ending theme maybe, but it doenst sound like an ending theme.
Other Shironeko Project extended BGM:
https://www.youtube.com/playlist?list=PLJSFfiBIf4LDlQUpy154dNJiRqeVQaZA3