I just noticed there is this akonadi directory taking a lot of disk space, about 8.5GB.

The directory is located at /home/user/.local/share/akonadi/file_lost+found/ and I'm wondering if I can delete it safely.

I'm also curious of why this is here and why is it so big as all my emails combined are in the 1.5-2GB range.

You can delete lost+found safely. It contains items for where there are no longer refereneces in Akonadi. Did you happen to run "akonadictl fsck" in the past?

Thanks for your answer, I'm gonna reclaim this disk space.

I don't remember running akonadictl fsck and it doesn't appear in my zsh history either, but I've had several issues with akonadi over time and followed a few different ways of attempting those issues I've found while searching the web, with more or less success. At some point I deleted and recreated one of my mail accounts.