Not on a P40 Pro unfortunately, we do things differently over here!Actually, you can use split screen on Nova Launcher. You just have to trigger it differently. I have no idea why. This is just the result of trial-and-error.
First turn on "force activities to be resizable" from developer options.
Now when in an app. Long press the recent apps button, release it and then press the home button. This works on my Samsung J500F with unofficial Lineage OS 17.1. Let me know if it works
Not in Nova, Huawei have changed the way the split screen works in EMUI compared to other android versions