Venerable Robina Courtin (https://www.robinacourtin.com) leads a short (22 minute) Vajrasattva practice including the Four Opponent Powers and the the 100 syllable Vajrasattva Mantra.   You can do this practice at the end of each day just by playing the audio and following the instruction. How good is that?    Begin by taking refuge, play through the audio following the visualisation and instruction and perform your own dedication after the audio ends with "be delighted, totally rejoice!!".   You can also read Kyabje Lama Zopa Rinpoche's advice on Vajrasattva practice.