Change chunksize running in FreeBSD Jail

I am trying to optimize my Nextcloud setup (NC21) running in a FreeBSD jail on a TrueNAS box.
My uploadchunks on big files are roughly 100MB what I can see in the client.
The documentation tells me to run the following command to change the size:

sudo -u www-data php occ config:app:set files max_chunk_size --value XXXXXX

But since I’m in FreeBSD and dont have SUDO I can’t figure out how to get this working. Is there a workaround maybe?