What should I do when I don't want to tell people that I've stopped a certain act of worship, so as not to be one of those who openly commit sins, but at the same time I don't want to remain silent about it so as not to feel like a hypocrite?

People's knowledge of your worship should be a motivation for you to act, not to seek their approval, but rather so that the servant's inner self is like their outer self, or better. This is exemplified by Abu Hanifa, who revived the night with prayer and supplication after it was said that he did not sleep at night.

And your informing people that you have abandoned a recommendable act of worship is not considered publicizing sin (mujāhara), for publicizing sin pertains to abandoning an obligatory duty.

It is not hypocrisy for people to think good of you that is not present in you; rather, showing off (riya') is performing an act for people to see.

Therefore, you are not obliged to inform them that you have abandoned this worship. Let your concern be to perform acts of obedience to the best of your ability.