I recharged with 61 twice (12/1/23 and 23/3/23) but no 5G invite. I am on 666 plan.
I generated Port code twice (1/12/22 and 25/3/23) to threaten them but still no 5G invite.
And secondary sim in my phone on 329 (which later changed to 395 plan) got 5G invite few months ago.
I tried everything like sim slot interchange, only sim with 666 plan, changing network mode, etc. etc. but no luck.
Anyway, I have made peace with it, I am shifting to Airtel (for other reasons, not 5G, my second sim will remain Jio) next month when my 666 plan ends.
My device is S20FE5G. Airtel's & Jio's 5G works fine. I have tested it myself in my own device.