The difficulty is a measure of how difficult it is to mine a Bitcoin block, or in more technical terms, to find a hash below a given target.
Before that, between May and July 2021, was a timeline when BTC network difficulty fell nearly 45.5% from 25.046 trillion to 13.673 trillion — at the time raising momentary concerns about the network’s vulnerability.
As shown below, the network hash rate eased down to the 220 EH/s mark by the end of the month with no visible negative impact on the BTC network difficulty.