Every win has its own value and feeling. It is not easy to win and whenever a player scores, it is a big achievement for them. However, evaluating different games, we would say that an Olympic medal is a much more monumental achievement. This is because, it is a much more watched event, it is a larger event and it has all the different countries of the world participating.
Hence, winning an Olympic medal means you won a title for your country. This is a much larger achievement than winning at the Wimbledon, which is nevertheless quite big achievement itself.
The more monumental achievement here would no doubt be winning an Olympic medal. When you say winning a match at Wimbledon, that could be a broad assumption. Would it be winning just a regular match or winning the entire tournament. Winning a Wimbledon title is certainly a very major thing but winning an Olympic medal would be more monumental in my opinion.
The Olympic medal means that you have won and are representing your native country. It means that you have truly been able to defeat the best athletes in the world and what it has to offer. Winning an Olympic medal also means that most likely more preperation was made in order to execute at a very high and optimal level.
If I were able to win an Olympic tennis medal it would mean so much not just for me but for everyone in my country. I get chill bumps each and every time I see the American Anthem played during the Olympic Games. I believe it would be more monumental to experience that inwinning an Olympic medal than winning a match at Wimbledon.