Everyone uses 給料 (kyuryo) when talking about their payment, which clippers always translate to salary. However the word can also mean wages, pay, or remuneration. It doesn't always carry the meaning of salary, and even then it can be used colloquially rather having the strict meaning of a fixed amount. Coco used it when talking her and Kanata's first payment, Lui used it when talking about her first pay, Lamy used it when talking about how her compensation went negative during merch production, Matsuri also used it when talking about her income near her debut. I saw one clipper translate Laplus saying 給料 as paycheck but they put salary in the clip title.
When Kanata said she earned 20000 yen in Feb 2019, she was reading a chat message which used 月給, which does mean monthly salary. However it wasn't her words, it was from the chat message.
Eventually calling their pay a salary spread to english-speaking vtubers even though I bet they have no idea what the word salary actually means, because all the EN vtubers are retarded clipniggers along with everyone in this thread.
