The following gambit appears to give Black enough to equalize. Careful play is required of both sides. The final position is clearly drawish.

When I give up a pawn I like to get a tempo or two and an initiative. Black looks solid and the Bishops are nice but that's all. Not sure that it will catch on, good find anyway.

Interesting game. At first glance, it looks as if Black has some compensation, but not quite enough. IM Larry Kaufman did a computer-aided study of thousands of master games, in order to determine the "true" value of the pieces. One of his conclusions was that the bishop pair was worth quite a lot--about half a pawn. SInce White is just as well developed as Black in your game, and both sides have sound pawn structures, then I don't see where Black has an entire pawns-worth of compensation. That's no reason not to play this line, of course. Black gets a nice, lively game for his money. I might suggest that 23.Bd6 is an improvement for White

How is that a good game for Black?

While I don't have time at the moment for doing some kind of deeper analysis, I would happily take a position where I am a pawn up for so little pressure from my opponent.

This line looks playable for black, but I think he is fighting for a draw from the 5th move onwards. His only compensation for the pawn is the two bishops, and with white having a solid position and not being behind in development, that is not enough.

     The basic problem facing White is this: Having an extra pawn is nice PROVIDED it can be converted into something bigger e.g. a promotable passed pawn. Here we see a situation where a set of minors goes off immediately. It is all but impossible for White to avoid the exchange of White's remaining Knight for the Queen Bishop. That leaves the dark-squared Bishops. Unless White can do something with that Bishop to gain some compensation, we just see a transition into a heavy piece ending which often, even a pawn up as here, are all but unwinnable.

     White cannot afford to get rid of all the minors without having at least a two pawn advantage. Surely, many of you know how tough it is to win a pawn up Rook and pawn ending. Here with the Rook and Queen combination, there is never going to be any way for White to avoid the checks and/or advance his passed pawn to do that. He cannot defend and advance the passed pawn at the same time, hence this is a draw.

     To provide any winning plan for White, you have to make progress. You cannot swap minor for minor, go into a heavy piece ending only one pawn up and expect to have any realistic winning chances. As such this line appears to be a dead end for White i.e. a theoretical bust because White has few, if any winning chances, with accurate play by Black.

     23.Bd6, Paul is no improvement unless you can demonstrate the win of material and the realistic hope of advancing a passed pawn in the bargain. As you know, there is an entire school of chess demonstrating a draw in the Rook, Bishop pawn and Rook pawn versus Rook ending that is a theoretical draw in many variations. Here, White doesn't even have that option i.e. this is even less winnable than known drawn Rook and pawn endings and Queen/Rook and pawn endings.

Where is this game from? If it's a game between mere mortals (i.e., you or me), I doubt that we can make judgements about move 5 by looking at the position 30 moves later. At a super-GM level, where play can be considered near perfect, the final position should be analyzed, as you suggest, if the opening is being debated.

Because there were no blatant tactical mistakes, I'm assuming this is being played at a very high level.

What we know for sure is that Black's winning chances in this line are zero, so there can only be one of two results: Either White wins, or it's a draw. I don't think I see the attraction for Black.

It's a standard joke that all rook endings are drawn, but this really applies to endings with pawns on one side of the board. When there are pawns on both sides, the chances for the side with the extra pawn get better. This isn't to say that I can demonstrate a win for White, it's just that White has a position where he can safely play for a win. At worst, he will have to settle for a draw. For Black, the most he can possibly hope for is a long defense with a half-point at the end unless he makes a mistake