Seafile store data in its own proprietary format. There’s no way to just go into the disk and browse the data. You need a proper backup solution.
In my case, I sync all my Seafile data between my server, laptop and desktop, so in the worst case I only lose the file history. A better option, if you have space, is to backup the Seafile storage volumes as well.
Seafile provides ready made compose files, with a detailed guide - https://manual.seafile.com/11.0/docker/deploy_seafile_with_docker/
Also, note that if you make an account on their site, you can get a free pro license for up to three accounts.
So, I had to double check myself on this one, and my original answer wasn’t entirely correct.
If it is found that the destruction of evidence was intentional then yes, the jury can be instructed to view the missing information in the least favorable light, or a case can simply be outright dismissed or a default judgement entered.
However even in the case of “accidental” (ie, not provably intentional) deletion the court can still take various measures to redress the balance in some way.
I am not a lawyer but this guy is - https://joneskell.com/how-spoliation-of-evidence-impacts-litigation/