Camera to Lightroom mobile to Google Photos = low resolution iOS

Hoping someone can help. 
From my Sony Camera, I'm importing full sized JPG images to Lightroom mobile, editing them and saving to IOS camera roll at maximum. From there I'm then uploading to Google Photos using the "high quality" setting, which is not maintaining the original size. I'm ending up with tiny files with a max size of 200kb, which started as a 4 or 5mb original off the camera. I'm not sure where I'm going wrong. My understanding was that uploading to Google Photos wouldn't change the size that drastically. At some point in the chain, I must be compressing this file to hell. Hope someone can help me.

{Thread renamed by moderator}