Please search the PowerCenter forum for this kind of discussion, there have been numerous posts about this topic in the past decade (and I'm too lazy to repeat them here ).
Personally I would always recommend Linux over Windows for a variety of reasons, but you should simply decide according to what you feel more comfortable with, not what guys like me recommend from their personal points of view.
The Short answer is you can use any OS from the PAM doc: PAM for Informatica Intelligent Cloud Services (IICS). It depends on which OS you are comfortable with, also selecting the latest version of the OS is recommended so that you can use it for a longer duration.
There are few advantages of Linux agent though
>> Linux agent is mandatory for Hadoop connectors
>> If you want to use complex files like Parquet, Avro then Linux agent is mandatory
If you don't want to use Hadoop or complex file then you can choose any OS from the supported OS in PAM