To expect an improvement in your rooms bass response I usually do at least two corners from floor to ceiling.
Most folks find this to be enough
I had a serious issue with my subwoofer output making my tonearm dance. My listening room is suspended over a two car garage and the bass was crazy. I used heavy/thick carpet pad with carpet over the hardwood floors. I spent months trying to relocate my turntable. I also installed 4’ high bass traps in the corners behind my speakers and at that point I had to decide to install 4’x3’x4” wall traps and so I eventually installed seven wall traps. My intention was to take the rear corner traps to the ceiling, but at this point my tonearm was much better controlled and I liked the sound, so I put everything on a very heavy rack and left things alone. I still haven’t mounted the wall traps, but my treatment was of the try it and listen variety. So, only you can decide what you are going to do and you can use acoustic modeling software, or just do trial and error. My speakers are rather short and I don’t think that I would have gone only half up the wall on my rear traps should my speakers been taller, but then again ports tend to be rather low, even on tall speakers. I can confidently state that the bass traps used greatly improved music reproduction. The bass is now very natural and has a pretty respectable fast, low bottom end.
PS - And don't forget the secret sauce, which is Bass Trap s+ EQ. You can use EQ alone to clip excess peaks and this can be huge, but with bass traps you can also tame some nulls.
Some can't put in bass traps, some can't put in EQ, so use what you can, but often the combination, properly dialed in, is the best.