R visuals in the Power BI service have a few limitations including:
Data size limitations - data used by the R visual for plotting is limited to 150,000 rows. If more than 150,000 rows are selected, only the top 150,000 rows are used and a message is displayed on the image. Additionally, the input data has a limit of 250 MB.
Reference:
https://docs.microsoft.com/en-us/power-bi/visuals/service-r-visuals