I compared how Excel spreadsheet is compatible with Excel, how many functions it provides, and how many types of functions.
The total number of functions provided by MS Excel is 504 (as of July 2022). (Refer to Microsoft site.)
The total number of functions provided by Spreadsheet is 494. (Refer to Google Site)
Please refer here for the one-by-one comparison of each function and the detailed analysis of function definition and explanation. In this sheet, I have compared the functions in this sheet as shown below.
What I felt when creating this analysis was that Google Spreadsheets now offers nearly all the important features, although it is not 100% identical to MS Excel. Google recently added a macro feature to Google Spreadsheets. This means that it offers almost all of the features that MS Excel has.
I know that MS Excel is different from the function of online office 365 and the function of installed Excel. In other words, browser-based online Excel has functional limitations compared to installed Excel. Google Spreadsheets, on the other hand, is 100% cloud-based and has the advantage of being immediately available with a browser and is also free.
See here for a detailed comparison of Google Spreadsheet functions and Excel functions.