We usually see very high on-chain activity during bull markets. This high activity further increases when the market crashes, as market participants scramble to get out of their positions. When the bitcoin price finally stabilizes at a low price, the on-chain activity usually drops to extremely low levels, as people lose interest. It looks like we are in such a period right now.
The average transaction value is back at its normal level of around $18k after sitting at the abnormally $37k last week, which was likely caused by the big market movements incentivizing market participants to move their coins into or out of exchanges. As bitcoin has stabilized at around $20k, the spot market has calmed down, and as a result, the large on-chain transactions have stopped.