fwiw, if your ISP supports vectoring, try different Lantiq firmwares?
The firmware supplied for free by Lantiq, and distributed with LEDE/OpenWrt is over 4 years old and does not support vectoring as far as I'm aware.
I think there is another much longer thread on same subject, but I don't have a link for it.
Regarding the random reboots, have you tried a different power adapter?
Good luck.