my phone was stuck in EDL and every msm i had said it was a mismatch. Basically, all MSM checks to assure it running on the proper device, except for the OP9 Pro variant. this allowed me to then use the original msm i needed (which is in my case, non pro global.
If unsure or doesnt work for you for whatever reason, there are a few guides in this OP9 forum on how to change from europe, global or whatever and even some specifically for switching to or from colorOS/OOS. id check them all out and see which way you feel is best for you.