I'm sorry to hear the results weren't what you hoped for! I know a few creators who did the same didn't recover their original stats. It's a risk to delete novels and start over, especially when engagement is more difficult for newer works with the site design change.
What I can suggest is, like you said, promoting your work on social media, the forums, and discord, though I dont recommend participating in the sub4sub stuff.
There's not much you can do besides waiting, keep publishing, and networking.