Afaik GitHub is for git only. While you can import existing git projects, pijul has its own web frontend called nest.

Everything else is significantly inferior

Which ones did you try?

There is pijul.

1. Pijul’s defining feature is its innovative algebra of patches model for version control, allowing changes to be applied in any order without creating conflicts, thus simplifying collaborative work.
2. It efficiently handles branches and merges, with its patch theory often enabling it to automatically resolve conflicts, eliminating much of the headache typically associated with merge conflicts.
3. Pijul is also free and open-source

Check this out: https://stackoverflow.blog/2023/05/23/for-those-who-just-dont-git-it-ep-573/