My three kids are the same ages. I don't know if it would be any easier if they weren't gt. because i also expect them to do a lot for themselves other parents might not. chores, showers, reading to each other, etc.
but yes, it is very exhausting because you don't want to ignore the "good questions" but the GOOD QUESTIONS come every 60 seconds between them... and the projects they want to do but require some much pulling out... and on and on.
It's not you. They can suck the life out of you. And not accepting that it is ok to feel like - come on give me a break - is like not letting a first time mom know that every moment doesn't have to be cherished and it isn't easy as we who've done it make it look.
If you find a magic solution to make it easier... let us know.