No issues here other than the crashing I had.
So far since disabling IPv6 I haven't had anymore crashes, the router has been up for a few days according to the system uptime. I will keep monitoring it, UPnP is still disabled for now. I haven't figured out why mine has an INP of 1.5 and a delay of 8ms on the downstream still (VDSL2), but I'll be moving house in a few weeks so I'll see if it still continues on a newly provisioned connection.