Official OpenVPN server install steps not working

Dear All,
I am trying to set up an OpenVPN server on my Xiaomi MiWiFi Nano router running OpenWrt 21.02.0 r16279-5cc0535800 / LuCI openwrt-21.02 branch git-21.231.26241-422c175 using this guide.

I must be doing something very very wrong, because others seem to have had success following it. In my case, I am using SSH from a Windows PC to do the config steps.

I get as far as 4. VPN service without any issue, but there the following line breaks with en error:

ls ${OVPN_PKI}/issued \
| sed -e "s/\.\w*$//" \
| while read -r OVPN_ID

The error is: ls: /issued: No such file or directory
Which is weird, because I can see the files:

root@R3L:~# ls ${OVPN_PKI}/issued
client.crt  server.crt

Any idea why it wouldn't go past this?

what does echo $OVPN_PKI say ?

root@R3L:~# echo $OVPN_PKI