Yeah, I could see Bg5 being better than Bf4, will concede that I hadn't thought of Bg5.
I ranked all 20 first moves for white.

Opening theory is the least of my worries and next to non existent these days to me.
I prefer to spend my limited time on basic tactics training, middle game plans, ideas, strategies and end games.
And having fun.
e4 openings are more fun because they are more open, tactical positions. You don't need to learn so many lines of opening theory when you have the tactical instincts to play e4 openings.
You need to know what to do against e5, c5 e6, and c6 as they are all common. Black also has several other moves white can easily get flustered against like the Nimzowitsch for example if white is unprepared:
Same thing with the Owens Defense:
Yes, this sideline is what Igor recommended. It would eventually lead to an equal game by most human plays. Your 4. Bf4 is too timid imo.