When I used Jira and Bitbucket in 2017, professionally as well, pushing a commit to Bitbucket with a message starting like "JRA-34", the branch and commits would show up in the Jira ticket. Since Jira's "new and improved" project version, they don't.
This is supremely frustrating, as the only apparent way to get them to show up is to create a branch from the ticket to Bitbucket, which automatically generates a ridiculous branch name that includes the ticket title, when the ticket title in the branch name is unnecessary (since ticket numbers are unique), overly-long (which can be hard to read, or push content aside in apps like SourceTree), and the ticket title can change based on it becoming more clear what the issue is about (which helps with search in Jira).
How it behaved in 2017 was sensible and easy and simple; how it behaves now is difficult and overly-complex. I don't understand why this change happened. I'm not seeing how to get branch commits to attach to the tickets when the branch is named after the ticket number and each commit starts with the ticket number.