Again the trickster inferior can fool us. More reliable than what you identify with is what your past behavior corresponds to.
Functions are a good way to get a handle on it, the ISTP functional stack is Ti-Se-Ni-Fe, but what you wrote about the functions isn't helping because you seem to say you do them all.
At any rate maybe past behaviors is the best approach. I'll pick out one in particular is your predilection for sports when younger. While not exhaustive, every INTP I've known and read about has disliked team sports, and at best participate in solo sports like running. Of those who run or whatever, never have I seen one that does it every day.
On the other hand the ISTP is a very sporty type. My ISTP brother has always been a sporty guy. ISTPs tend to be well developed physically while INTPs tend to look like Beaker from the Muppets.
ISTPs are close cousins to the INTP, I'd suspect you are one with the INTP being your inferior (tertiary) attractor.
While I generally respect your opinions, your argument is literally, 'you are like other ISTP's that I've known, so you're probably one too.'
But the paragraph I posted was specifically designed to demonstrate what I have done that has developed my Se. It's a very minor part of my personality and none of it is what I'm necessarily interested in.
Note that I called the tasks requiring Se at my work, 'boring and nit-picky.'
I fucking
HATE having to physically fix equipment, but it's simply way too costly to call a contractor out for every minor problem that doesn't require one. Since I don't want to waste money in calling them out, and I don't want other people calling them out for problems that can be fixed on our end, I do it myself. Essentially because I know that if I don't set the expectation that managers learn and actively repair and maintain equipment, I know that it's going to negatively impact profit.
Profit which ultimately allows me to spend more time at work doing the things I enjoy - long-range planning and brainstorming ways to improve the business at large.
Essentially, I complete only those 'S' tasks that are a minimum requirement of my job description. Anything beyond is delegated to people who are either better suited, or who don't have anything more important to do. When I say better suited, I generally mean people of relatively equal authority - we simply divide the work up into what we're all good at and go from there.
I agree with you entirely that past behaviour is the most effective indicator, but the example I gave is a really small portion of my overall behaviour. Like you said, we can turn it on whenever it's required, and to the outside observer it will be barely noticeable that we're faking it.