I sometimes wonder if we need a better phonics. Doing it by letters feels crude, it requires a big gestalt moment when the kid puts the sounds together, and overemphasizes our very malleable vowels. Something based more on syllables would seem better to me. Consider a simple work like “back”: kids sound out buh-ah-kuh which is a completely crazy version of the real word. You can’t say a B without a vowel, but instead…
So boil will have a dot under b, one under o-i and one under the l.
They can then spot that oi is a digraph; in the early stages they do this by saying out loud, an o and a i make 'oy'