We can all be pedantic, why do you have to be alive to exist?

Depends on the specific definition of the verb existing we are talking about, right?

90% of "I'm too autistic"-insecurities boil down to words being not clearly defined (or them being clearly defined, but either people using them without care or you not being aware of the definition they use). A word isn't magically stuck the the abstract concept it refers to, people can mean different things while using the same word. In philosophy for example it is very apparent that one author's definition of existence (or any other abstract concept, like freedom) may differ fundamentally from another author's.

We can all agree that sometimes the use of an word has unfortunate side effects, like turning something simple like existence into something you can suck at. This often boils down to (A) a use of the concept we are not aware of, e.g. if Paul Satré used the word existence, he has writen thousand page book on his specific meaning of the word and the author having read Satré unbeknownst to us refers to Satré's definition or (B) the author just chose a word that sounded cool and picked somewhat imprecisely.

I think here (as so often) it is the latter, but to cut them some slack: colloquially people will say things like "I feel like I am not even existing/alive". And what they often mean by that is that their life passes in full automation mode, with them barely having any present thought at any moment — wake up, commute, work, rinse, repeat. If that is your problem, doing something that gets you out of that automation state is good.

However I believe that many pasttimes can do that, e.g. playing music, climbing, a walk through an unknown landscape, etc. I am pretty certain there are indigenous people out there who probably don't even know of this problem to begin with, they simply just exist in their present moment. So this isn't generally hard for a human being. But it can be hard to some.