itch.io

Wow, you even found a nice site with lots of free SFX. Thank you.
As for Blue Archive assets, I managed to get voiceovers not only for the characters but also for the movie voiceovers and some SFX. I can't seem to extract what I was originally looking for though, so I will give up on that. Fortunately, these alone are a great help already, so thank you for showing me the way, I will use it well.