In the stock camera app. The hdr++ doesn't take long multiple shots like it was on android pie. No circle animation in the center.
The image is the same result as hdr+ auto.
I can see a noticable difference between those two modes...and i have updated to android 10,...sure it doesnt take much time but i think it works fine
In the dark I believe it may choose to use HDR+ also as the results can be seriously poor with HDR++ Enhanced in low light (it is not made for that, use Night Mode).