The cracked glass is the digitizer and it is what detects and transmits the touch. A crack can interrupt the signal. Try using voice input and see if it works fine. You will probably just need a new screen replacement.
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=== Update (06/13/2020) ===
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The cracked glass will cause touch issues. You could try settings you touch sensitively but I believe you need a new screen.
The cracked glass is the digitizer and it is what detects and transmits the touch. A crack can interrupt the signal. Try using voice input and see if it works fine. You will probably just need a new screen replacement.