scvi_normalized values contain small non-zero values which make the dot size the same for all dots. You can use a cutoff of something like 0.1 and rerun it.
Gernerally, I prefer starting with log1p values for dotplots.
It might make sense to use the scvi_normalized values if you need a batch-corrected expression value (most of the times not essential).
As we show in the tutorial other visualizations like heatmaps don’t require a hard threshold at 0 and are preferable for usage with scvi_normalized values.