I have a Huawei nova 3i and I remember unlocking developer options when I first got the phone a few months back. Problem is now I have noticed that the developer options are gone so I went to build number and went to press it 7 times but after the first press it says (you are already a developer) but the option is still not there. I have looked online for at least an hour but can find nothing. Any help would be appreciated thanks
I had the same exact problem with the mentioned phone and none of the provided solutions worked for me. Finally i succeeded to make the developer options visible by going to settings - apps - selecting "settings" app and executing "clear data" on it. It worked with me.
If the Developer options menu refuses to appear there is an alternative:
Use the very tiny app Developer Options. It allows you to enter the developer options menu independently if you have enabled or disabled it.
Once you are seeing the developer options menu check the switch on the top for enabling/disabling the developer options. Try to toggle it several times and in the end leave it enabled. Now check if the developer options menu is visible.
If this does not work use the app again to enter the developer options menu and change the developer options switch to disabled. Then try to tap again the build number 7 times. Hopefully afterwards the developer options menu appears. If not you can keep the "Developer Options" app as workaround. In difference to other apps it does not contains tracking, adware or advertisement frameworks (at least the version I have checked - v1.0.4).