Does anyone have a suggestion for a reliable password generator

"Reliable" doesn't really fit. Either the app works and generates passwords, or it doesn't.

The one I used for a long time is 32 bit and no chance of being updated to 64 bit by its author. I tried a bunch of them from the App Store, and I think the free GenPwd works very well.

That's a Mac password generator. I haven't looked to see if there's an iOS version.

Keychain access does that. It will even do that as your are filling them in.

1Password has built-in password generator which is complete integrated the application updates and changes.

What programming language? One can already generate strong passwords in iOS 12.