The global key available in your settings should be 2048 bits long, can you run the following in one of your workspaces to confirm (the first 4 digits of the output are the bit strength):
ssh-keygen -l -f ~/.ssh/id_rsa.pub
An explanation of this command can be found here:
The SSH key should be 2048 bits, and is used by SSH workspaces, and I believe with GitHub and Bitbucket, so I’m not sure why it wouldn’t work. Can you post a screenshot of the error you’re encountering on Bitbucket?