I can’t hide photos any more

I tried it on my phone. When you press the share icon, an option to hide should be on the menu that pops up. If not, tap Edit Actions and see if you can add it.If none of this works, try restarting your phone and/or updating to the latest version of iOS.

In Settings, check Photos. Here, you will find an option to toggle Hidden Album on and off - check to make sure it is on.