I don't think Solus software are "underdeveloped", some Solus's technologies are being rewritten right now, and this takes time, it is a small team compared to other commercial and non-commercial distros out there, heck they don't even want donations(plzdontbanme).
But, as I was saying eopkg will be deprecated, in turn we'll have sol, and of course the software center will have a major update too, the actual 3rd party applications will be unused and replaced, and it will support flathub/snap.
And of course you can always use flatpak and snapd from terminal, it is fully functional, and it's not hard, there are some github projects that can help you if you want a gui for this.