Short answer: For a Jain shravak (layman), wearing a dhoti is fine, but modesty (lajjā) and vinay are essential. In practice, keep the chest and stomach covered—especially in temple premises and during any puja, sāmāyik, pratikraman, or vrat.

Simple guidance:

• In the temple and for all rituals: Wear an upper cloth (uparaṇā/angavastra) or a kurta with your dhoti. Avoid a bare chest and midriff.
• Daily life at home: A dhoti is acceptable, but prefer to keep the torso covered to uphold modesty and avoid distraction.
• Fabrics and style: Choose clean, simple, light-colored cotton; avoid flashy designs, leather, silk, wool, or anything causing himsā.
• Sect note: Digambar muni’s nudity is a monastic vow and never a model for lay dress. Both Śvetāmbara and Digambar traditions expect modest clothing from lay followers.

For brief temple and clothing norms, see:

• Basic rules when visiting a Jain temple
• What to wear during mantra-jāp/pujā (simple, modest, usually white)