Save prior results from table

The good option to to pull the data into a database or warehouse before pulling into Power BI to keep a history.

A hacky way would be with incremental refresh. You could include RangeStart and RangeEnd to effectively do nothing, but are required to active the policy. Create a refeshDate column in powerquery set to today(). You would set the active window to a day and archived for whatever period you want keep. On refresh you'd get your new data in the active partition with the date of export. This would then rolling to the archive window the following day. You will need to bootstrap by first publishing to the service, then use tabular editor to apply the policy. Then can refresh as normal, this is to avoid filling the archive partition. Side note, if the schema of the table ever changes you may lose your partitions, depending on what you change. Realtically should go for option 1