One of the reasons for this is
"Mempool Congestion"

The congestion in the Bitcoin Mempool significantly impacted transaction processing times and fees. With a growing number of transactions competing for validation, miners prioritized those with higher fees.

Mempool or memory pool refers to a backlog of pending and unconfirmed transactions in a blockchain. These unconfirmed transactions wait in the mempool to get validated and finalized in the upcoming block.