Hey Delilah,
I ran into this before a family trip & the fix for me was to stop fighting the camera when it got too dark. For portraits in dim rooms I went to manual focus and watched for the little focus confirmation to light up and then shot a short burst so at least one frame was perfect. Surprisingly reliable. For group shots I flipped to the rear screen and used magnification to check eyes, braced my elbows on a chair back or a doorway, and let the ISO climb so the shutter stayed fast. Pre focus at the distance where people will stand and wait for them to land there rather than chasing them with the focus box. If someone is moving, switch to continuous focus and keep the point glued to the face while you half press and track.
