Does the keyboard have the correct settings on the console at all?
Because the question is asked before the kernel is loaded (it needs to be able to decrypt the disk before it can load the kernel from it) you should probably look in loader(8). But I fear it's not able to change the keyboard layout. If you uefi(8) boot instead of CSM there maybe more possibilities as EFI applications can do quite a lot more. But I never looked too deeply into this, I'm used to the bog standard US layout.Any hints for documents I could not find during my research?
#where to put the key
zpool status
pool: zroot
state: ONLINE
scan: none requested
config:
NAME STATE READ WRITE CKSUM
zroot ONLINE 0 0 0
ada0p3.eli ONLINE 0 0 0
#add key
geli setkey -n 1 ada0p3