Seing a trend between two dates is an easy feast within our report tool. Looker studio also allows you to see a trend easily, but won't let you sort your tables by trends.
This mean you can't create a top 10 drop or gain in position, or simply check your most versatile keywords.
However, you can do it using blended data.
Requirements:
A data source using the keyword entity
filtered datasource (or use Looker studio filter) to have only 1 type of result and 1 device
First create a blended data, using twice the same data source.
You need to use a custom date range for each table, with the second one corresponding to "Previous period".
For example, for a monthly frequency data source, you date range could be "last month", and the second one would be "Advanced date range" set to "Minus 2 month".
Then you go for full outer join set on keyword:
Finally, you need to create a chart field, using the formula
"Position (date 1) - Position (date 2)", and name it Trends
The result will show you the difference of the last month vs previous period.
You can then sort this result out to determine if you gained positions or lost your rank.
However, keep in mind you need to use the correct date range depending on your tracking configuration (monthly, weekly, daily...).