Recent versions of OpenSSH (9.6+) display the warning below when connecting to Bitbucket Cloud:
 

WARNING: connection is not using a post-quantum key exchange algorithm. This session may be vulnerable to "store now, decrypt later" attacks. The server may need to be upgraded. See https://openssh.com/pq.html 

please support for PQ-hybrid KEX algorithms in Bitbucket Cloud to align with industry standards, reduce warnings

If you want to hide these warnings (cosmetic only):

Host bitbucket.org 
    LogLevel ERROR