Items on canvases are *significantly* smaller when built than in Unity Remote?

So, I tested out my game in UnityRemote, and my buttons and UI text were all about the size I wanted, so I went ahead and built the Android version, and pushed it to my phone. (The *same* phone that I ran UnityRemote on).

The built version of the game has *way* smaller buttons and UI text. Maybe 1/5 the size of what they were before, if that. They are small enough that the buttons are pretty much unusable.

The only possible contributing factor that I see is that during the build, I got some "Failed ETC2 compression" and "Failed ETC1 compression" errors, but I can't seem to find much on getting rid of those, nor can I see how those could be causing the UI canvas items to shrink.

Has anybody seen this? Is there a solution? I didn't see much about it on google...

Edit to add: I tried building again, and this time I didn't get the errors, but I still have the tiny canvas items...

I have verified that all of my canvases have UI Scale mode set to Scale with Screen Size, so I don't think it's a scaling thing...