There is no info reported in DSL status overview (ie. no DSL sync), that's why OpenWrt is reporting 'Network device is not present'.
ie. Valid Annex, Tone and PTM/ATM are the only three settings required for DSL sync.
(VLAN, PPPoE etc does not affect DSL status overview)
It is possible the Lantiq firmware/blob which is supplied for use in OpenWrt upto 21.02 (which has not changed since 2016) is not compatible with your ISP. eg. it does not support Vectoring is one obvious missing feature.
The Lantiq firmware/blob included in Netgear DM200 OEM firmware will support Vectoring, and/or compatible with your ISP.
If you are not able to extract the Lantiq firmware from the Netgear firmware, another forum member may have a copy.
There is a separate forum thread for Lantiq firmware.
https://forum.openwrt.org/t/lantiq-vrx200-xdsl-firmware-recommendation-thread/52937
(See also section 7.27 of my guide)
fwiw, I don't know if this page maintained by xdarklight is up to date or not.
http://xdarklight.github.io/lantiq-xdsl-firmware-info/
I forgot to add OpenWrt 22.03 prerelease may include a new Lantiq firmware/blob which supports vectoring. I could be wrong though. (note 22.03 also uses DSA, so any previously posts about DM200 bridge mode won't be valid due to changes in syntax in /etc/config/network file)