Here are some respectful Jain tap completion wishes for Upadhyan / Upadhyayan:

1. Upadhyan tap ni hardik anandmayi badhai. Aapnu tapasya jivanne pavitra ane shuddh banave.
2. Tapashcharya sampann thava badal hardik shubhkamnao. Bhagwan Mahavir aapne anant shakti aape.
3. Upadhyan tap ni purnata par aapne khub khub vandan. Aapnu vrat ane tapa safal thay.
4. Aapni tapasya ne namaskar. Aapnu aatma-bal vadhe ane moksh marg ma pragati thay.
5. Upadhyan tap ni sampurnata par dil thi badhai. Aapne param shanti ane pavitrata male.
6. Aapnu tapa anek janmona karmo ni nirjara kare. Shubh bhavnao sathe vandan.

If you want, I can also make these into:

• short WhatsApp wishes
• Gujarati wishes
• formal Jain blessing style