Hello @Roy de Kleijn ,
Thanks for reaching out.
When we show the lab user's name in the list, we pull the givenName and familyName properties from AAD that your account is part of.
If your name shows up as a GUID, that's something that is set at your organization's AAD level, so you would need to talk to your AAD admin to correct it. this isn't something we control at our level.
Hope this information helps. Please don't forget to "Accept as answer" and "Upvote " the same if the reply is helpful.