Here is a really good seed if you are looking for an ocean monument. It will literally take just 10 seconds to get there (if you are in creative mode). It might be a bit hard to discern in the water, but just drink a potion of night vision and you won’t be able to miss it.
The spawn is on a small survival island situated far out in the ocean somewhere. Just straight ahead of spawn you will be able to see the ocean monument on the bottom of the ocean floor. Make sure to set brightness to max if you can’t see it. Drinking a potion of night vision will also help seeing it.