Withe very large number of ES and SES on the upstream side there is clearly something not right.
It'd be worth running DSLstats against one or both lines for a while so you can better understand what is happening when the line drops. REIN is unfortunately a distinct possibility if the issue is of an intermittent nature.
The upstream numbers don't reset on many Lantiq chipsets, including Drayteks.
I've seen new lines report tens of thousands of ES/SES. I think it's historic figures reported by the DSLAM.
Those upstream numbers might be months or years worth.
It could also just be a really bad line and they are accurate.
The difference between attainable (max rate) and the sync speed suggests something is very wrong, particularly with retx on both the downstream and upstream.