Is it better to renounce Qatari citizenship to marry in India, or to wait for permission to marry from the Qatari government, taking into consideration the opinion of some people that giving up Qatari citizenship is considered missing a "golden opportunity"?

Remaining in Qatar and maintaining your original nationality is better for you from both a religious and worldly perspective. This facilitates your visits to your mother and your care for her, as well as making it easier to provide for her financially should she need it. Despite the importance of the emotional aspect, circumstances may necessitate prioritizing other matters. You can still strive to marry the young man who desires you by submitting a request and seeking assistance from charitable people. In case of rejection or a prolonged wait, be content with what Allah has decreed, for the good may be elsewhere, and perhaps someone better will propose to you.