Artix is basically a “new” distro that intends to be built & supported by the maintainers of a combination of other non-systemd distros that have been using the OpenRC init.
A prime reason for the large number of downloads is that Artoo (the main man, re. OpenRC) has left Manjaro (where his OpenRC work has been quite welcome & greatly appreciated) & taken his OpenRC support with him. The split was due to the difficulty for Artoo (& his ilk) in maintaining OpenRC in Manjaro, which is very much based on the systemd based Arch’ repo’s.
Re. the Artix forum, it really is very early days for Artix at this stage. They have a great deal of work to do in the setup of the distro, & the forum will/should get growing support by the maintainers as time goes by (when they can afford the time). Hopefully they will have some members of the forum that are amenable to providing some beginner friendly support, as unfortunately Artoo is not the best person for that job.
Another thing to remember, is that many of the Manjaro users that use OpenRC are relatively new to Linux, & are therefore more inclined to read, absorb, possibly puzzle, & keep their mouths shut, unless they have struck a problem that they need help with.
All of which is fine, requiring encouragement & needing no negative judgment (at least at this very early stage in the life of Artix).