When you first start you get cactus but there isn't sand anywhere. You can't buy sand and there is no sand on the island.

There is one way of obtaining sand but that is from wandering traders, it takes a good 3ish hours for them to spawn and when they do you’d need to have found a way to gain emeralds to trade for the resource, so in the meantime I would recommend trying to generate some emeralds through villager trades

Mistake when making the new shops

We also need lava or at least obsidian. Do nether portals work?

South:

We also need lava or at least obsidian. Do nether portals work?

No. there is also no way currently to obtain more lava (other than add burner accounts as members of your island)

Those are also items I forgot to include in the shops, they'll be updated soon. Dunno how I forgot considering I made all new islands for the nether.