i know this is good to miners reward
but not to users

i want to know what cause this skyrocket in fee after halving 840000
It is halving 840000, Spam began as many people tried to have their transactions included in block number 840000, and since the size of the block was limited, there was competition over fees reaching more than 5k sat/vB.
The average block time is ~9.8 minutes, which means that we may need a longer time to return to normal fees.