Check out Linear. The startup I was at nearly switched to Jira and then thankfully when a bunch of us protested, we tried Linear and ended up really loving it.
The issue list where your Git repos are hosted. For example, GitHub is pretty amazing. GitLab is nice too. There's also Gitea, which looks like GitHub, which is pretty amazing.
I have tried GitHub project boards for hobby repos and was disappointed by how bare bones it was. For example, it did not have support for breaking a story into smaller component stories (like a Jira Epic or task with sub-tasks).
It might be an unpopular opinion, but Azure Boards has worked well in small and large orgs that I’ve been at. Some teams I’ve worked with also used GitHub projects, depending on your source control and other providers.
I worked with Azure Boards and the entire TFS stack for multiple years and it's a horrible experience. It's very slow, buggy and especially the access-management is so poorly designed, most engineers had admin rights, because we tried for hours and ended it with "fuck it" and gave them admin rights, so they could do their job.
My previous company used Jira, and my current company uses Gitlab. For sprint management it works fine.
There might also be a philosophy aspect relevant here regarding 'if your sprint management becomes too complex you might be misusing scrum/micromanaging too much'
Also curious what others here think about using gitlab for this, do you think it lacks features?
Since everyone's placing their favourite non-mainstream non-opensource forge, I don't feel as bad simping for jetbrains space: https://www.jetbrains.com/space/
It packs a lot of the intelligence of their IDEs, which comes really handy.
Mainstream and open source, I'd go for heptapod, i.e. gitlab with mercurial support: https://heptapod.net/
Why mercurial? Because that's everything you ever wanted git to be (with proper branching via topics, and convenient and safe history rewriting/traceability to collaborate on PRs).