what if I have a bedrock account with the same username (Pizza4001) as my java account (also Pizza4001)
For the moment, we don't have an answer for whitelisting a user who has the same xbox gamer tag as their java edition profile. These are still early days of our bedrock support, and some things are still a bit rough around the edges.
If you really want to, you could. I wouldn't recommend it, if you really like your gamertag. As I mentioned, these are still early days - I expect that, at some point, we'll have a solution where gamertag and java username are the same. No eta on that, though. If you want to change a username: There is a cost (from Microsoft) to changing your xbox gamertag (might be after the first change). So, if you really want to change an account name to remove the conflict, and you're not overly attached to your java username, it's probably easier to change that. The whitelist request allows a user to indicate whether they're using bedrock or java. As a reminder for all readers, you must be 13 or older to submit a whitelist request. Otherwise, get your parent or legal guardian to help. update: You're faster than I can type! Now you just need to log into the game with your java user. That should change your forum user name. After that, you can submit your new whitelist request.