While it might be off-topic for a community port of Sailfish OS, there is unfortunately one step one should do for basically any Sailfish X device - increase the size of your rootfs!

Due to unfortunate situation with the default Android partitioning the default rootfs on Sailfish X devices is very small and has a low amount of free space right after initial installation. As all apps are installed to rootfs & upgrades need free space there as well, this can quickly become a major issue. In general I recommend to do this as soon as possible after installation or make sure you have everything backed up if you do it later on as a filesystem resize is needed, so better be safe than sorry.

And for the future, I guess it could be solved by spanning the LVM layout over the two partitions (two physical volumes in the LVM volume group) and having the recovery images on an LV as well.

That way no space would be wasted and root would be big enough by default, so hope Sailfish X moves this way in the future.