...5 nxe4 is not a bad move after d4 b5 bb3 d5 dxe5 Black has be6 and I do not see what is wrong with their position.
Ruy Lopez
There's nothing wrong with the Open Defense, 5...Nxe4 (indeed, I'm surprised 5...b5 seems to be more popular at the master and GM level), although the Closed Defense, 5...Be7, is significantly more common.

Victor Korchnoi would definitely disagree with the opinion that Open Spanish is unpleasant for black. He won many brilliant games in this line against the best GMs of his times.
In fact, Karpov says in his books about the Ruy Lopez that Open is one of the sharpest lines and gives black good counterplay if white plays inaccurately.
5...Be7 is definitely more popular nowadays but that was not the case at the beginning of 20th century when Open was frequently used.
Also, note that white should be aware of the move order:
7.Bb3 0-0 (instead of d6) 8.c3 d5 leads to Marshall Attack which is a very dangerous weapon in hands of players who specialize in that line

The Schliemann with 3..f5 is a very interesting line. I wish it was played more often vs Fischer to see what he would have done. 1)e4 e5, 2) Nf3 Nc6, 3) Bb5 f5!, 4) Nc3 Nd4!!, it may appear that white has several good options, but my own experience has been that black has counterplay and can gain the advantage if white makes even the slightest inaccurate move.
Hello everyone! I am writing this to share my knowledge of the Ruy Lopez with you, and hopefully give you something new.
Okay, so we all know that the Ruy Lopez is 1.e4 e5 2.Nf3 Nc6 3.Bb5 but it is the ideas after this that are what we need to understand. My chess engine gives the position after 3.Bb5 +0.17 and white will normally start to squeeze Black with his extra space.
Here the main move for Black is 3...a6 but other moves are 3...Nf6, 3...f5(more of a computer move if you ask me) and 3...Bc5. The above moves are easily the most popular third moves. First we will look at 3...a6
Now the two, just about only moves, are 4.Ba4 and 4.Bxc6. 4.Ba4 is much more popular, according to chess.com's database it is used about 45,000 more times than 4.Bxc6. So we will make a few more moves in the main line.
My engine gives this position +0.05 but I don't agree with that, I think it is more like +0.25. White has set a trap, because Black is not well advised to take the pawn with 5...Nxe4 because of this line.
So, instead Black will most likely play 5...Be7. I will skip some moves to get to what I find a critical position.
8.c3 is the start of a very important idea of breaking in the center with d2-d4. So Black will likely castle with 8...0-0
9.h3! is very strong because it prepares a deep plan of stopping Bc8-g4 pinning the knight and giving d2-d4 some problems, planing Nb1-d2-f1-g3 with pressure. Now to sum up my lesson I will give a game master game from this position.
Thank you, and I hope enjoyed!