Since vectors don’t have rotation associated with them, I’m assuming that you are treating this like a region 3 except with a point instead of parts. You can do this with each axis.
if X>math.min(X1,X2) and X<math.max(X1,X2) and
Y>math.min(Y1,Y2) and Y< etc etc

Being honestly, I’m not good at searching things because I’m sure there’s a post but I use different keywords and I don’t have too much time so I decided to make a post.

It doesn’t matter, that’s why math.max and min. If I did make it matter, you would have to be careful to place one of them at higher XY and Z values. It would be slightly more efficient if you did that, but you’d have to be very careful that you placed the boundaries in the correct corners. I’m certain this way is good enough and that you will not need to worry about the small performance boost.

In other words it functions like region 3 does and it takes two points in any configuration.