I support the views of both experts. I further opine that although FAQs say that there is no provision for payment of GST under protest but in my view erstwhile provisions are saved under Saving Section 174 of CGST Act. Saving Section protects the interest of both i.e. Assessees and Govt. Various courts accept the payment of tax under protest. There is practice to this effect. The purpose of "Under Protest" is to provide natural justice to the assessee. If you pay tax under protest, it shows your bona fides and hence saves from penal action.
No need to pay interest at present. However, interest can also be paid under protest.