If you do a "dry-run" of raiding the monument, aka without Water Breathing, this is a decent approach. Under the Mining Fatigue effect, you take about 370 times longer to break blocks and your attack speed is reduced by 30%.

Learn How to Raid the Ocean Monument Quickly and Easily and What things to bring to an ocean monument, how to defeat elder guardians, guardians and How to Find and Clear an Ocean Monument...

An explorer map is a special map used to aid in finding rare generated structures, including woodland mansions, ocean monuments, buried treasures and trial chambers. Apprentice-level cartographer villagers sell ocean explorer maps for 13 emeralds and a compass.

You absolutely need water breathing and invisibility potions. The gaurdians will kill you super quickly even in netherite. You need to take off all your armor for the invisibly to work, but you can keep your boots on.