is there any way in Discord4j to get someone's username using their id? The only way I have found so far is using UserData.builder().id("id").username("username").discriminator("0000").build();, but this requires you to manualy specify a username. Is there any other way?
You should not be building D4J
DataXclasses yourself.DataXclasses are the raw JSON mappings of what Discord sends and are mapped using Jackson.To get a user from ID:
GatewayDiscordClient#getUserFromId(userId)