Question Regarding Data Refresh Frequency and History

Pro supports Hourly refresh, pick Daily, pick an hour then create another refresh, pick Daily, pick another hour, etc. If you need more frequently you should investigate Direct Query or a streaming data source. Using these methods, you can get "live" data (up to the second)

Currently, refresh in Power BI is always a complete refresh of the data. So, your situation, you would need to keep the other data around somewhere and append your current data. You could do this with an R script Query and an Azure SQL database for example. You would create a query that grabbed everything from your Azure SQL database. You would then create another query that grabbed from the data source you mention that only holds 2 days of information. You would do this in R, for example, and this query would write back to the Azure SQL database with the new information. You would then Append this query to your first query. In this way, you would get everything. I believe there is an Idea for incremental refresh. Ah yes, here it is, you should vote for it:

https://ideas.powerbi.com/forums/265200-power-bi-ideas/suggestions/7288623-incremental-data-loads