Nope, it's not because of that. New firmware with new kernel+more changes vs EMUI 10, that's why poor battery life and other stuffs. I would reccomend you a factory reset and if you have an OTG adapter+USB device and a C431 device, flash the dload firmware from my other thread to have all just like out of the boxI have used your guide on EMUI 10.0 and been very satisfied. The phone worked flowlessly.
Now after update to EMUI 10.1 my P30 has been slow, and drains battery a lot, such on bleutooth.
Maybe some of Huawei services are missing, and I can just try to install those by adb command.
I know that I can reset the phone, but I have a lot apps, and will avoid new installations.