Hello,
Sorry, Even if it is limited to web-based access, RDS CALs are still required to use RD Web Access.
If you mainly use RD Web Access to access file resources on the server, you can use the built-in file sharing services of Windows Server, such as SMB protocol, to allow users to directly access files through network drives, etc., without using RD Web Access, which can avoid the need for RDS CAL.
For some specific applications, consider deploying them as web applications that can be accessed directly through a browser rather than connecting to a remote desktop session through RD Web Access. This eliminates the need for users to use RDS CALs and allows them to access the application.
I hope this information helps.
Best regards,
Jingjing Wu