I would apply and then spend time considering when you hear if you are in. The past few years there were more applications than spots so it is not a given at all that you will get one. I'd apply to Arlington Tech and HB and see where you get a spot. If you get one, they give you opportunities to learn more and decide if it's a fit (not sure how they will do it with Covid but normally they have kids spend a day shadowing a current 9th grader).
In short, don't overthink because there isn't a high chance your child will get a spot.