Is it obligatory to repeat the ‘Umrah for a woman who completed its rituals while she was menstruating, knowing that she stipulated this condition upon entering into Iḥrām, and it is difficult for her to return to Makkah?

You must repent to Allah for circumambulating the Kaaba while menstruating. There is no need to return to Mecca to complete the rituals, because you were prevented from completing them due to menstruation, and you had stipulated (a condition) at the time of your ihram.