I did some testing on my Android device and wasn't able to duplicate the issue. My device has a bit more power than yours, so I think you may be right about the Tab A's specs causing problems.
Date an Otter's gallery is a bit different on the back end from my previous VNs, so it's likely a bit more demanding/unoptimized on those screens. I know a way I can reduce memory usage on these screens, but it'll have to be in a future patch. I don't know when/if that patch may come, but you should still be able to run other VNs (Date a Mink's free if you need something to test) .
Also, I'm happy to hear this issue didn't get in the way of the story! ^^