The whole concept of SunBird/Beeper apps is very dumb, allowing some 3rd party to access your messages is total fuck-up.

Disable all folders, except DCIM in google photos settings, so it won’t upload anything, but photos made with camera.

I used it too, the biggest issue is no webdav support, than zip support is bad, pdf viewer is bad, no built-in image viewer, so you always switching to gallery (it is great, but switching back and forth is not good) eventually I decided why using two file managers instead of one and CX is really good and simple to use.