Right now the very rough plan is ~ 14 chapters.
So chapter 8 is not the final chapter. It is a decent stopping point tho if you wanna play like half the game and then wait for more.
( Chapter 4 will be free faaairly soon too, which is also a good stopping point. )
But don't hold me to that rough chapter estimate at all. I thought I could get the whole beach section done in a quick chapter but I spent an entire year on it and split it up over 3 chapters because I kept adding to it and it got super ambitious.
I'll try not to let that kinda thing happen again though.
So yeah, the full game will probably take 2+ years to be completed.