Adjust predicted probability after smote
No, any adjustment to the probabilities will presumably be monotonic, so the rank-ordering of the predictions will be the same, so the AUC will be the same.
See, e.g., https://datascience.stackexchange.com/a/58899/55122


See also the more complex "probability calibration" techniques.

Also, if you see better results after smote+undersampling, and can share your data and work, I'd be very interested.  I haven't yet seen an example where training on the original dataset doesn't do just as well (with appropriate thresholding).