Do they all do the same thing?
For 80% + use cases, yes. But each product has its own niche and its own unique functions.
SSRS is the clear choice in a clean MS development environment. It enjoys huge MS support and infrastructure support and has many built-in integrations with other MS products such as Excel and SharePoint.
Crystal Reports has momentum and history on its side. It has no less mistakes than others, but it has many mature user groups, forums, etc., which leave only a very thin chance that you will have some problems that others have not had, fixed and published answers. In addition, many companies have come across this as their standard tools, since prior to the SSRS, no products threatened CRs market leadership. (Not that SSRS immediately threatened CR, but since SSRS was provided free of charge as part of SQL Server, it developed a large number on the principle that SSRS is usually "good enough" and does not require additional licensing after you pay for SQL Server
I am not familiar with Fast Report, and my understanding of Stimulsoft Reporting is that it works well in environments where multiple types of data sources are used.
I wonder what tools or technologies should be studied and used?
Assuming you need a job working with these tools, the answer lies in the market in which you want to work. If your job market hires mainly for a specific reporting system, this is not a problem: look at the one that your local company mainly hires. (It sounds obvious, but I constantly see young technicians studying a specific product for academic reasons, and then I am disappointed that local companies are not interested in the product to which they devoted their training energy.)
If your job market is neutral (or you donโt care where you get the job), I would recommend sticking with big players (SSRS, Crystal Reports - players in the list you specify), because work is more plentiful there.
From there, choose the philosophy that you like best: (Beware, generalizations ahead) SSRS works best in MS-oriented environments and is used by higher peer companies because of its price. If you like new developments, small companies and startups, this is your choice. (My opinion: SSRS is a growing product that is fully supported by Microsoft. It has not yet reached its golden age and will continue to improve in future versions of SQL.) Crystal Reports is noticeably larger in large enterprise environments with many databases and long lists of legacy systems. If you like larger corporate environments and supported installed systems, this is your choice. (My opinion: โCrystal reports had their golden age in the 90s and are gradually declining in market value. He will continue to be a major player for decades, but I donโt see them ever returning.โ 90s a place ".)