Budget lens recommendations for lowlight street photography and indoor family photos / E-M1 mark ii body

Hi everyone. As the title says. I am new to photography and just got my E-M1ii body + Oly 12-40mm F2.8 secondhand and was wondering if it’s enough for low-light indoor family photos and at-night street photography. I am looking into adding maybe a prime lens with better low light performance that can potentially cover my use case. I’d appreciate your suggestions!

Thanks in advance.