Do we have t late fee/interest if the portal is not automatically asking?

For the GSTR 3B which was due on 24 July 2021, I transferred the challan amount through RTGS but it only got credited today (26 July) which means it is 2 days late. When I open the GTR-3B, and try to offset the liabilities to file the return, it doesn't ask for any late fee or interest.

Do I need to pay the late fee and interest and mention in the GSTR3B? I was told that late fee is automatically prompted on the portal but it is not being prompted.

So should I file the return as is or also pay the late fee and interest and mention in the GSTR-#B before filing? Also, is the interest rate 18%? (It for the quarter April-May-June 2021).

Thanks in advance for your help