Well, that probably depends on your definition of "the endgame". The main story about MC's dad will be part of the next two updates and should basically conclude by then, which would leave the "prom part" to be completed. That's going to take time.
I made calculation quite some time ago based on DC's official roadmap and base on the time it took to release updates during the last 2 years. Accordingly it should likely take another 3 to 3,5 years until the basic game is done. After that there's of course quite a bit left that could be done (pregnancy sex, more scenes in general, small stories for some minor characters just like Consuela's now, etc.), which will probably get done at least partly, as long as enough patreons want it.
That said, the game will reach a point, where DC could technically finish it without breaking too many promises, so it may indeed be shorter, too. Which would be really sad, though.