If you imagine a box around a syllable, then give every syllable a constant amount of room for that box, you’ll get writing that looks very bad. Negative space especially will build up
You can contextually adjust the size of a letter and the space it’s allotted on 2 axes, and how much you do both depends on whether you’re writing vertically or horizontally
Roughly, you should let syllables vary in the dimension of writing and reduce variation in the transverse dimension. You may have to stretch or compress individual letters to make the whole syllable more consistent