Some words will be hard, and that is the entire point of practicing them. A word that a child finds tricky is not a problem to fix on the spot — it is simply a word to come back to.
When a word is hard, let your child hear it again. In Articarry they can tap the word to hear it read aloud as many times as they like. Hearing the model, then trying once more when ready, is plenty — there is no need to drill it.
Resist the urge to correct. Saying “not quite, try again” turns practice into a test, and a young child stops wanting to play a test. Let the recording be made, let the picture appear, and move on.
The clinician will hear every recording, including the tricky ones. The tricky words are the useful signal — they are exactly what the clinician wants to listen to. Your job is to keep the practice happening and gentle; theirs is to listen.
This guide is general help for families, not advice about a particular child. For anything specific, a child's speech-language pathologist is the person to ask.