It's not there... Actually looks like I don't have fw4 at all:
root@router:/usr/share# nft
-ash: nft: not found
root@router:/usr/share# ls
acl.d/ dnsmasq/ libiwinfo/ luci/ udhcpc/
advanced-reboot/ fw3/ libubox/ rpcd/
...
root@router:/etc# cat openwrt_release
DISTRIB_ID='OpenWrt'
DISTRIB_RELEASE='22.03.2'
DISTRIB_REVISION='r19803-9a599fee93'
DISTRIB_TARGET='mvebu/cortexa9'
DISTRIB_ARCH='arm_cortex-a9_vfpv3-d16'
DISTRIB_DESCRIPTION='OpenWrt 22.03.2 r19803-9a599fee93'
DISTRIB_TAINTS=''