Yes, you can perform Umrah while on a visit eVisa.
From the official eVisa website:
8.7 An eVisa is granted solely for tourist purposes or for the purpose of performing a umrah and it is not considered a visa for work. If you are granted an eVisa, you must not take up paid employment during your visit to KSA.
Yes, you can perform Umrah on a Saudi Arabian e-visa.
From this news article:
Among the most important features of the Saudi tourist visa, is the visa holder can benefit from it in performing Umrah, women need not be accompanied by a male relative, other than in the Haj season, and there is no need for a sponsor (kafeel) the way it is required for work ...