finding a player

[BeastlyBot]

so a couple days ago, around 7/28/21, I was in a server with someone. they were building a big nether themed castle and i was helping them, but i logged back on a few days later and the server was reset. their name was 11 characters and something like RydiaR---l but i dont remember the full name. can anyone help
not telling the server name just in case

[Checkmate128]

Did he ever create a chat message? If so, you can go through all of your client logs that we're generated on that day and look for his username because chat messages are logged by the client. They have a little "[Chat]" prefix too so you know what is a chat message.