Time to sync and excessive storage usage

I installed Unstoppable wallet last week, imported my Zcash wallet, and I've been waiting for it to download and sync blocks all week. My network speeds are fine - it's not a bandwidth issue. I've found that it doesn't progress unless I leave the app running in the foreground with my screen unlocked. So, for most of the week, I've had my screen timeout set to 30 minutes, and my phone has been churning through the blockchain. Last night it finally finished, and I saw my Zcash balance! This morning, it appears to be using 20GB of space, my phone was full and not very responsive. I've had to delete many of my apps just to make room for it. It also seems to have fallen out of sync again. It's now trying to sync again starting at block 1575287...

This is not usable for me in it's current state. Is there anything that can be done to sync faster and use less space?