Man you got super lucky!
Is this easy? I'm on the fence about it.
It's extremely easy. In every fight, just spam B.
Press B to not die. Got it!
This help make merchant voyages faster?
Don't think so unfortunately, just allows you to buy full crates of resources from merchants straight away. Could be nice for fruit crates tho
Find an underwater ruin - Minecraft (Android)
Using the Frost Walker boots, walk on at least 1 block on frozen water on a deep ocean - Minecraft (Android)
Acquire a map from a cartographer villager, then enter the revealed structure - Minecraft (Android)