i do think a really missable etho trait that is defining to me is that. you may think he's a luddite or opposed to changing his routine on principle. and it's true that he's really prone to doing things whatever fucked up way he's used to. but also he's very adaptable and will pick up whatever new way of doing things with no fanfare at all. so whichever part is more obvious to you makes the other half more consternating. but it's like, if it ain't broke don't fix it - and what is "broken" and what is "beyond repair" is contextual.
he also micromanages contexts if he has control over them so you get tricked into thinking oh he's like This - not exactly, the LP's constraints definitely produce habits such as not using even vanilla-adjacent mods because it's an original Rule or whatever but the moment he isn't controlling the context/has to adapt it's like well here comes freecam and flashback segments in hermitcraft! because the Rules are actually crafted for the audience's sake/engagement.
ultimately he's a guy who puts insane amounts of effort into being maximally lazy. he'll collect 5 stacks every block in the game for his ender chest system at the start of every season... so he won't need to build things first in creative and again in survival. he will "fix" his stupid out-of-production headset until he literally can't anymore so as not to have to deal with replacing it and if the replacement is too much work he'll go back to the garbage familiar thing. it is perfectly logical if and only if you have the exact same preferences, constraints, and habits as etho. but fortunately he also loves pissing people off by being weird and off-putting. so he has very little incentive to change/actually make people understand.