Snapseed does have limited brush abilities. You can dodge/burn, adjust exposure, and I think white balance is the third option. I like this app because it's easy and is the only one I've found to handle my LG V20 RAW files correctly (all others with RAW capabilities on this phone glitch and result in a 1MP low resolution jpeg export). That said, this seems to be a bug unique to this phone. I've also had some color retention issues on this app.
If you want to have a photo editor you can draw on, give this a try.
https://play.google.com/store/apps/details?id=com.iudesk.android.photo.editor
I actually use this for adding text, and it's a surprisingly powerful editor. A lot of the features are beyond my skills/understanding. The downsides are no RAW support and it's a very manual oriented editor. For example, where the Snapseed text editor gives you style templates to work with, this one let's you build up your text from scratch like this:
View attachment 286693
That took me about 10 minutes to create just playing around with some features I hadn't used before when helping another poster out on here.
Lastly, I often use Photoshop Express. Because of the RAW bug I mentioned earlier, I can't use it for my phone's RAW files, but it does handle multiple RAW file formats. This makes it handy if you are a photographer that wants to import your full sized camera RAW files for editing on your phone. In most cases I edit my RAW's in Snapseed and export as a jpeg, then open that up in Photoshop Express to do final touch-ups. The de-haze and various noise reduction options are very handy.