If your model has the rear Multiview camera you might find it better just to turn the parking sensors off.
Personally I find the camera sufficient for reversing into parking spaces. Not yet used it in very bad weather that may affect the camera visibility ,but this could affect sensors as well. As for front sensors, well call me old fashioned, but I actually look out of the front windscreen myself. .
I do leave my sensors on, but there have been times when deliberately reversing into long grass,near soft foliage, or out of a gateway, that the system lights up like a Christmas tree with flashing lights,and beeping .Information overload at times, especially when I know from also looking round and in the rear camera that there is no problem and plenty of space.
I do like the cross traffic monitor on the EX but probably wouldnt upgrade specially if thats all you get.
I dont know if the bleeper is just that - a standalone beeper rather than integrated into a loud speaker thats needed for other things.. If you can locate it and get access maybe you could physically muffle the sound in some way. (But it would be unfair to the next owner not to reverse it when the car is sold)