When the first word of a vocal line disappears, it is natural to turn the vocal up. But a strong guitar downstroke on the same beat can cover the first consonant even when both parts are loud enough. Instead of changing the whole mix, isolate the one bar where the vocal entry and guitar attack collide.
Listen to the first beat before changing the whole mix
A buried first word does not always mean the singer is too quiet. If the vocal consonant and guitar chord attack arrive together, the lyric can blur even at a healthy level. Pick one entry that sounds crowded and listen to which part takes the front of the beat.
Loop one beat before and two beats after the entry
Looping only the word misses the guitar attack that causes the problem. In Jium, include one beat before the vocal entry, the strum itself, and two beats after the first word. That short loop should contain the breath, the chord attack, and the first consonant.
Use part mixing to alternate the front position
Bring the vocal forward first so you can hear where the first consonant actually lands. Then bring the guitar forward and notice how hard the chord attack hits. If both parts jump out at the same instant, you can decide whether to soften the strum or make the vocal start clearer.
Compare two takes by first-word clarity only
Record one take as usual, then record a second take with the first guitar strum slightly softer or with the accent moved after the word. In take comparison, ignore the full performance for a moment and judge only whether the first word is clearer without losing the groove.