1. 5th Edition Core Rulebooks are going away.
Well yes. They will be replaced with the One D&D versions of the books. Which are confirmed to NOT be digital only. This reads as fear-mongering and slightly deceptive; One D&D (which be it 6e or 5.5) will exist come 2024 in both dead-tree and digital, much like 5e does now.
2. The SRD is incomplete.
Intentionally, to stop another Pathfinder from reprinting the PHB/DMG/MM as Paizo was able to 2009. However, that does mean a lot of re-inventing the wheel. You already have shown off the "not-eldritch knight" and "not-battlemaster" fighter subclasses.
It does lead to a strange predicament though: If your books are intended to be an "evergreen" version of the 5e rules, you have to basically cover what has already been done by 5e. You need to make your own versions of assassins, chuthulu-warlocks, moon druids, and the like. Or else, you going to say "this isn't a replacement for 5e, but more like our remix of it".
So Project Black Flag isn’t a new game?
As much as One D&D is going to be. Both games are making major changes to races (both in terminology and mechanics), class progression, spells, monsters, backgrounds feats/talents, and similar. While the changes are the same exact as WotC, they are changing similar pain points and sometimes finding similar answers (spell lists, streamlining subclass progression, etc).
So far, all I've seen is an alternative to One D&D for people who want to upgrade but don't want support WotC. I won't debate if your changes are better or worse than what WotC is doing, but so far, I feel they are on par with the scope of change. If, in 2024, I'm looking at the BF player's book or the 1D&D PHB, which one I go with will solely depend on which one I feel has the superior version of changes. I hold no lingering animosity towards WotC for the OGL debacle, and I'm not sold that what I've seen so far is any better than what WotC is offering.
Focus on making the product, because this type of rhetoric isn't moving the needle.