To join with a Bedrock client, link your Bedrock account to your Java account by logging into both on the GeyserMC account linking page. Then message Curtis (archpenguin) with your Bedrock username and Java username. If you don't do this first, each account will be separate and have different permissions, inventories, etc. Also, if you join them later on, you'll lose your Bedrock inventory, as the Java account takes priority.