Google analytic g4 drop too much data traffic while GWT appear at steady number

Hi. Since 15 february our site start lost traffic at google traffic g4. The weird this data traffic at google webmaster tool gwt show steady number
Didnt show any drop
We also already check several our primary keyword at steady number of ranking

If anyone know what the cause of this issue, let us know. Explain the problem how you will solve this issue. Thank you.