It doesn’t slow charge, at least not on Pixel 7a. Well, you could argue whether 20W is slow charging, but it’s all this phone can do.

It just charges normally to 80%, stops, and then resumes charging about an hour or two before the alarm. And last time I used it, it had a cool bug where if it fails to reach 80% by the point in time when it’s supposed to resume charging, it will just stop charging no matter what the current charge level is. Since that experience, I just turned this feature off and charge it in whenever it starts running low.