over time with frequent (2-3 x per week) handling they will likely calm down for the most part.

However, if you don't want to have to deal with the inevitable bad hair day of a big boa, there's no shame in trading for a BP. Everyone has their limits, likes, and dislikes.

In my case, I am probably more like you - what I did was buy a BCA that will always stay smaller than my BP - he has his moments of thrashing but the small size makes it OK for me to handle on my own.

There's nothing quite like a BP
If you're interested in trying other placid, docile snakes, a Woma Python might be something to check out.