From UFS to ZFS as root on RBPI4

From: Stefan Parvu <sparvu_at_kronometrix.org>
Date: Fri, 19 Aug 2022 08:29:07 UTC 
Hi,

Do we have anywhere documented any procedure how one would move 
from UFS to ZFS for root using RBPI 4GB / 8GB RAM ?

I want to convert some installations to use by default ZFS on RBPI. Would
this even work for systems with 4/8GB RAM? Is it difficult?

Thanks,
Stefan