Using AV2 with T4 Sumner gear to hit multiple targets 60% of the time. Using Apex skill wintara to clear low hp mobs. I rushed to floor 10, then cleared all tower guardians. There is a slight edit in the video where I backed out after the first floor to reset my anguish.
It took me just over 17 minutes to do the 50 floors and gain 31k shards.
If you had several 50 floor towers queued up, you can expect around 100k shards per hour without any shard boosting event or shrine.