How can one protect the soul from returning to sin after repentance, and is publishing religious content instead of the previous content that displeased God considered a form of showing off (riyaa')?

Publishing good deeds and Quranic recitations instead of unlawful content is a good deed that expiates sins, as Allah Almighty says: "Indeed, good deeds do away with ill deeds," and the Prophet (peace be upon him) said: "Follow up a bad deed with a good deed that will wipe it out." So, do not stop doing good and strive against your soul, seeking the pleasure of Allah.

To protect yourself from returning to sins, stay away from bad company and replace them with righteous ones, for "a companion is a drawer," and "a person is guided by his close associate."