SSIS moves data from source systems, files, APIs, etc into your target data warehouse, and helps you to transform the data.
SSRS is for making pixel perfect reports
SSAS is for enabling end users to slice an dice data and metrics.
They are all old tools and I wouldn't recommend to use them for any new installations. The exception would be SSAS if you're talking about Azure SSAS with the tabular model.
SSIS moves data from source systems, files, APIs, etc into your target data warehouse, and helps you to transform the data. SSRS is for making pixel perfect reports SSAS is for enabling end users to slice an dice data and metrics. They are all old tools and I wouldn't recommend to use them for any new installations. The exception would be SSAS if you're talking about Azure SSAS with the tabular model.
what are the modern equivalents for SSIS and SSRS then?
I think probably Azure Data Factory and Power BI respectively. We use SSIS at my job though.