The Closed Ruy Lopez is an opening that rewards solid, comprehensive chess knowledge up to endgame knowledge. The whole system is therefore very difficult for newcomers to tournament chess. If you play this variation, you need to know that the better player has the best chances of winning in the Spanish.
The closed Ruy Lopez is an extremely demanding opening. The starting position, after 9. h3, offers both players many opportunities to pursue their ideas. And there is no other opening variation among the open games that is so demanding for both sides and at the same time so instructive. Taking this aspect alone into account, our recommendation would be that both White and Black should endeavour to play this opening for at least some time. Because here you not only learn Spanish, but a lot about chess in general.
On the other hand, the challenges posed by the closed Ruy Lopez clash with the sporting expectations you have as a player. It may well be that you learn the most in this opening variation, but not every game of chess is just training.
Everyone must decide for themselves how important short-term sporting success is and how important the individual game is as training. And if you decide not to play the Closed Ruy Lopez, you should look at the basic ideas and the most important games with this opening. You will learn a lot about other chess openings and can return to this queen of openings if the circumstances are right.
Would you like to learn this opening? You can find specialised opening training courses here: Closed Spanish (chessbase.com)