Minecraft wiki entry for Best_biomes_for_homes, associated text: Living in this biome without items from the Overworld is brutal.
To get to the outer islands, the player must either bridge to them, use a flying machine, or kill the ender dragon and get into the end gateway, either by using an ender pearl or placing water and swimming into the gateway.
The player may end up falling into the Void, meaning the player will lose all their items and experience. This danger is especially high on bridges that are 1 block wide or have no railing.
Once the outer islands are reached, the player will need to head to an end city for tools. These structures are quite dangerous due to the shulker mobs scattered about. Given that the only thing the player will be armed with at this point is ender pearls and chorus fruit, the challenge comes with making it to the chests at the top of the towers/the end ship without being able to efficiently kill shulkers. While the towers are designed so that all areas can be reached by foot, albeit requiring parkour while under attack from shulkers, with the exception of the ship, the shulker bullets will prove difficult to avoid. A few ideas include using the shulker's bullets to your advantage to levitate upward, although it requires the consumption of chorus fruit to keep your health up, which may teleport you back down a few blocks. You could use the chorus fruit as well, in hopes that it progressively teleports you upward. The best strategy is likely using ender pearls, although you will need many, which requires a lot of bare-handed enderman farming.
Crossing to other islands can be achieved by either: throwing ender pearls or making bridges of chorus plant blocks. Once the player loots an end city, they could build block bridges or use elytra.
Endermen are everywhere and deadly to an unarmed player, so keep your head down and avoid eye contact.
The player will likely be using a lot of ender pearls, which can occasionally spawn endermites. While weak, they attract enderman which can teleport or walk in front of the player's vision.