how to move cursor left and right in a router's busybox shell

my router runs asuswrt merlin. the /bin/sh is packaged in BusyBox v1.25.1 (2017-12-02 00:49:46 EST) multi-call binary. my question is how do I move my cursor one word left and right? with bash, i can do option+left, option+right, which is mapped in terminal to \033b and \033f respectively. on my router's shell, it just prints a b and an f. so how do i remap shortcuts in shell or what out of the (busy)box shortcut is there? Note 1: i found that busybox supposedly packages ash shell, so my question may be how to move cursor one word with ash shell. Note 2: i tried enabling and disabling the following option to use meta+b and meta+f, no luck Note 3: added apple and ash tags