Those aren’t git features, those are features provided by surrounding tooling, not git itself, so I didn’t really consider them. I also never used them in private projects.

However, issues you can migrate easiely. I’ve seen tools out there that copy the issue content from github and to somewhere new. The creator of that issue is then a bot user or something, but the issue is still there and can be worked on. On github, the bot will leave a message that this issue is now handled somewhere else and closes it. Done.

Pull requests are also simple, you just merge them all. I haven’t seen a lot of projects with hundreds of open pull requests that were lying there for weeks or months. Now yes, you will lose the comments and history of the pull request itself, but I don’t think that’s very important.

Tasks I don’t know. I’ve never used them and don’t even know what they do. If it’s just a glorified kanban board with plenty of cards that say “Do X”, you can just copy paste them to your new tool because there’s nothing technical about them.