Login to
https://pnbcard.in/portal/index website and activate the card from the website, you should be able to activate it, then for all online purchases, you can able to use the card even with Bhim UPI. From the Mobile genie app card activation is not working.
My wife's card was also approved on 21st Nov there is still not any information about the card dispatch status, however, we have already activated the card and started using it for online purposes.