The pair is something of a simplification, and romaji makes certain things in the language more obvious. Like the good old mat-u -> mat-anai, mat-imasu, mat-eru. Added the hyphen to make it clearer, but this hyphen splits a kana neatly in half. The stem is “mat” but you can’t write the stem using kana (in some sense of the word ‘stem’, maybe that’s not the correct word and there’s a different word for it, I’m not a linguist).

I’m not trying to say you should avoid kana, just that there is some amount of intuition you can develop with romaji that does not work in kana.

Have you considered that different things are difficult for different people? Learning hiragana and katakana has taken me about a month, and I found it very difficult. There is no need to make it prerequisite for starting to learn grammar, forming sentences, or pronunciation.