MS-SQL SSIS/SSAS/SSRS Licensing

"...Reporting Services, Analysis Services, Integration Services, and so on. If these components are installed, location matters. If the non-engine components are installed elsewhere, such as another VM which may be better from a performance or application standpoint, they are licensed separately. For example, if one VM has SQL Server 2019 but another has Reporting Services, both VMs will need to be accounted for when it comes to licensing."

https://blogs.vmware.com/apps/2020/07/licensing-microsoft-sql-server-for-vmware-vsphere-part-one.html
SSIS is NOT a client licensed component. It is a server-licensed component.
You cannot install SSIS client tools without using a SQL Server license. However, you do not have to install SQL Server on the SSIS client tools box if you do not wish.
You can install SSIS client tools using a Developer Edition license in a development environment, assuming all SQL Servers are properly licensed (Enterprise or Developer) and all developers using SSIS have developer licenses.
You can use SQL Server Standard Edition if you don't need some of the transforms and destinations:* Data Mining Query Transformation* Data Mining Model Training Destination Adapter* Fuzzy Grouping Transformation* Fuzzy Lookup Transformation* Term Extraction Transformation* Term Lookup Transformation* Dimension Processing Destination Adapter* Partition Processing Destination Adapter
The above has been distilled and paraphrased from various comments here: https://social.msdn.microsoft.com/Forums/sqlserver/en-US/6ce7599a-930d-47a9-8fd6-358bf9ed9ef2/ssis-licensing-question?forum=sqlintegrationservices