Yes, you could. The limit is for the source dataset size but you can prefilter it (there is an option to pass in free-form SQL query instead of table name when creating a diff).
For the majority of diffs we see with sampling applied, sample sizes are <1M rows (more is often impractical in terms of information gain for higher compute costs) especially if your goal is to assess the magnitude of the difference as opposed to get every single diverging row.
For the majority of diffs we see with sampling applied, sample sizes are <1M rows (more is often impractical in terms of information gain for higher compute costs) especially if your goal is to assess the magnitude of the difference as opposed to get every single diverging row.