Chen Xi didn't pay too much mind to Zhuge Liang's behavior; the man was simply studying what he enjoyed. As for military formations, Chen Xi's own level was akin to a Spearhead Formation. When it came to the other potent formations, he had realized that mastering them would definitely require a substantial amount of effort.
Regarding formations, Chen Xi had inquired about them. Most military generals knew only a handful of conventional formations. As for high-level tactics like the Eight Gates Golden Lock, even Liu Ye had a superficial understanding. Of course, someone like Guo Jia, who understood Mystical Tactics, was not included, as his advanced cultivation was precisely in these areas.