What you are looking for must be Copperspice: https://www.copperspice.com/ It checks all your boxes, since it is a hard fork of Qt, but doesn’t use the moc and only an open source licence. Since you haven’t even tried to explain why you won’t use Qt, it is a little difficult to help with an alternative.

That being said, it really sounds like what you are looking for is Qt 🤷

Well, technically the horse wasn’t his…

One of the reasons they got through with it is that the big three already has it, so I guess… Update and read the documentation of your compiler of choice?