If you want to host your own genealogy tree all options were (are) fairly janky. Gramps.js is the best options in my opinion.
Why now?
They finished core features that let you manage the tree fully online.
Gramps started as a desktop java app... and that desktop app works but synchronizing it is mess. The Gramps.js repo started using same data structures just new UI and finally they added delete function finishing CRUD bigo.
This means you can use the web app without ever using desktop app and since it is all hosted everybody who cares can contribute ~~without~~ with less of a risk of corrupting all the data.
Cons.
I think gramps.js is still incredibly janky (you have multiple objects that are handled independently for a single record i.e. family and person) and the maintainers priorities are bazar (implementing delete 2 years after starting the project and adding UI niceties like maps and alternative graphing views...)
Importing.
If you have your genealogy on some site somewhat curated you should be able to export most of the core information and import into Gramps.js (pictures can be an issue). For the import you may need the desktop app to convert to correct format (desktop app still has a lot more features and if you need to do merges I recommend using it ).
David (primary author) seems a great guy and works pretty diligently on this.
It worked well enough as a test instance for me a bit ago. I guess I could stand it up again and see just where it's at now. Gramps, for me, is still by far the best family tree software assuming you don't want anything cloud related.
It is an amazing effort to make any project and I think it is grate that he is doing it... still... it took version v23 to starts deleting objects?