I figured it out. The problem is the number in the filename. I changed it from RalSurcharge2 to RalSurchargeTwo, now it works...
If it still not works, then it can be because the file events.xml is in the wrong folder. I wonder why it ever worked for me, normally it has to be in MODULE/etc/webapi_rest
https://magento.stackexchange.com/a/189439/66769