Problem with colleague

Hi guys, I'm here for some advice regarding an episode at work.

Basically a few months ago I started in a new company, and in the same period also another developer with 15+ years of experience (I have 5). Right from the start, I noticed that he had much more difficulty than me in learning the company codebase, but I thought "everyone has their own learning times, I'm not his boss, it's not my problem".

However, our team leader assigned us a project to work on together and we decided how to divide the tasks. After about 1 week I finished my part, so I offered to help him with some of his work, after 3 days I complete that part as well. Basically only 15/20% of the work remains to complete everything, I send him the name of the branch on which I made the changes to the code and continue with other things I had pending. After two days I see him create a PR with only the code implemented by me, without the “assigned to him” part, so the job wasn't even 100% complete.

Now I felt a little teased, as well as not having done his part, it would seem that he also wants to take the credit for mine. I suggested in private chat to create the PR only when the job was finished, but he ghosted me completely.

What would you do in my situation? Thanks and sorry if the text is a bit long