hmm, strong Overlord feel, only the MC starts out far less composed then most (read as all) MC's in stories like this (transfer to a game he plays) and if i may say, his reaction if far more realistic then those others who is disturbingly calm and quick to come to terms with and accept their situation, Ainz, of course, is not included as he has a system, skill, undead feature, whatever you wanna call it that supress his emotions and straight out prevents him from reacting to anything with strong emotional outbursts exept for a few handfull of times where his sudden emotional outbursts overpowered the "system"
oh, and his theories besides the 3rd one is dumb af, the first one can not possibly be possible without hardware upgrades as well, and teh second one is just pure stupid in every concievable way possible, the only part in that one that is even remotely possible is the cosplaying as that one character thing, the rest is just pure stupid nonsense so not sure what the author was thinking when they came up with that shit.