I suggest we can differentiate books we already learned from books we didn't in inventories (different shades or colors), it's quite tedious to check every time whether I completed the book already, there are too many to remember by heart.
As for the gyrocopter, I was hoping fly model would be closer to one in Rust (which has challenging controls and need a bit of training, but is absolute blast to fly while respecting physics the best it can). Is there any reason why I cannot use mouse move up/down as pitch out/in? Space/C feels especially cumbersome and banking doesn't feel it has much impact (again, compared to Rust gyro). Also vertical landings and especially takeoffs would be much more helpful in difficult terain.
Other than that, game is absolute blast and got me hooked, it's amazing how the game is evolving adding new layers and systems. Some of new POIs are absolutely stunning dive, systems such as electricity add so much to base building and defense. Turrets are also great addition, sort of 'companion' for people playing solo, they can now have something to cover their back while digging or looting.