There are so many missing functions which should be added. Just take a look at functions available in Excel for starters. Functions that work on ranges should work on collections or arrays.
Math:sin,cos,tan (and all their derivative) ,abs,sum (across a field in a collection or object), sumif, sumproduct, avg, count, round, countif,countblank,countifs,max,maxif
String: instr, left,right,proper,rept
Conditional logic: ifs,iferror,ifna
The list is so huge, see https://support.microsoft.com/en-us/office/excel-functions-alphabetical-b3944572-255d-4efb-bb96-c6d9...
We do support the range functions through Office Scripts. You can set formulas, set values, re-calc, get values, get text, read formulas, etc.
See the screen shot below.
Checkout these resources to see how to use Office Scripts in Power Automate.
Step-by-step videos and source code + PA flows: https://github.com/sumurthy/officescripts-projects
Official site: https://docs.microsoft.com/en-us/office/dev/scripts/overview/excel