On FreeBSD You have ZFS with ZFS Boot Environments - which gives GREAT flexibility and protection against all kind od updates, changes and even accidental files deletion in the system. Moving to 'oldschool' LVM and EXT4 is just a huge downgrade. Especially without any advanced features such as compression or snapshots or clones or ... all the other wonders from ZFS.
As from the busybox ... You can also use it on FreeBSD - its under 'sysutils/busybox' port ... and FreeBSD has 'kinda' itself busybox-like solution - its called FreeBSD Rescue System and its located at /rescue. It contains one executable file 17 MB in size (and ZFS lz4 makes that 11 MB) with hardlinks as commands - including all needed ZFS commands - which BusyBox obviously does not have.
FreeBSD % % du -sm /rescue
11 /rescue
FreeBSD % du -smA /rescue
17 /rescue
FreeBSD % ls /rescue
[ dhclient gbde kldstat mt rmdir umount
bectl dhclient-script geom kldunload mv route unlink
bsdlabel disklabel getfacl ldconfig nc routed unlzma
bunzip2 dmesg glabel less newfs rrestore unxz
bzcat dump gpart link newfs_msdos rtquery unzstd
bzip2 dumpfs groups ln nextboot rtsol vi
camcontrol dumpon gunzip ls nos-tun savecore whoami
cat echo gzcat lzcat pgrep sed xz
ccdconfig ed gzip lzma ping setfacl xzcat
chflags ex halt md5 ping6 sh zcat
chgrp expr head mdconfig pkill shutdown zdb
chio fastboot hostname mdmfs poweroff sleep zfs
chmod fasthalt id mkdir ps stty zpool
chown fdisk ifconfig mknod pwd swapon zstd
chroot fetch init more rcorder sync zstdcat
clri fsck ipf mount rdump sysctl zstdmt
cp fsck_4.2bsd iscsictl mount_cd9660 realpath tail
csh fsck_ffs iscsid mount_msdosfs reboot tar
date fsck_msdosfs kenv mount_nfs red tcsh
dd fsck_ufs kill mount_nullfs rescue tee
devfs fsdb kldconfig mount_udf restore test
df fsirand kldload mount_unionfs rm tunefs
... and do not get me wrong - I like Alpine (same as Void or Gentoo or Devuan) - its just not the same thing.
... and its even possible to setup Alpine with root on ZFS - https://openzfs.github.io/openzfs-docs/Getting%20Started/Alp... - it will just take a quite large amount of work while on FreeBSD you just select 'Auto (ZFS)' installer option and hit enter.
Hope that helps.