Can a Service Exporter under LUT Opt for Quarterly GST Filing?

I am an IT freelancer registered under GST in Tamil Nadu.

• I export IT services only (no goods)
• I file LUT every year
• I raise one export invoice per month
• My GST liability is NIL (zero-rated supply under LUT)
• Turnover is below ₹5 crore

Currently I am filing GSTR-1 and GSTR-3B monthly.

I am considering opting for the QRMP (Quarterly Return Monthly Payment) scheme to reduce compliance burden.

My doubts:

1. Is a service exporter under LUT eligible for QRMP?

2. If tax liability is NIL, do I still need to generate PMT-06 challan in the first two months of the quarter?

3. Are there any practical issues in refund processing or compliance if I switch to quarterly filing?

4. Is there any specific restriction applicable to service exporters?

Would appreciate clarification from professionals who handle export-of-service GST compliance.

Thank you.