If I were you I'd run DR. You get 3 per run and you only need to do 5. You could run POTD 51-100 in the same amount of time it takes to do 1 DR and get nothing. It is completely random and certainly not more efficient.
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Last time i try PotD with a friend we clear 51-100 and 51-80
I loot NOTHING and he loot 7 artifacts
PotD can be very fast OR very very very slow.
You could always keep an eye on the Party Finder. People set up speedruns pretty regularly. Just make sure you bring some essences and lost actions to do your part and you'll have 20 minute-ish runs, maybe quicker. It's a bit of an investment, but if you don't like the place it might be worth it.