This app was mentioned in 2 comments, with an average of 4.50 upvotes
Just to be clear, you're always gonna sacrifice some quality when you compress. Same holds true with Google Photos.
That said, one app I've grown fond of recently is Photoczip. It's the most permission friendly, no B.S. image compression app I've come across, & it comes with a good selection of settings for various size & quality outputs.
Photoczip (I hope the link's working; Play Store's broken for me atm) allows you to quickly select photos, compress them, zips them and offers to let you share them quickly.
It's a very specific usage, but it's very useful for me because I have to process a lot of photos I take while I'm at work.