Dear Emmanuel,
You can change the keyboard shortcuts as you want. If alt-ctrl-up/down arrow is too much hassle for you, do as some experienced users on this forum : if you have a num pad on your keyboard, set this octave jump to -/+ on your pad or whatever feels natural… By default, I think no key from the num pad is used (Dorico has been developed with laptop keyboard in mind). You can set the octaves on the fly (but it’s another combination of notes, ctrl-pitch for lower, alt-shift-pitch for higher), but if you have created an octave jump that suits you, it can be faster to enter the note and then move it (and sometimes, you don’t have a choice, if the interval between two adjacent notes is too big.)