"All the functions" - I guarantee you that almost any function you want in Excel is in Sheets. Just because you don't know how to use it or find it doesn't mean it doesn't exist. The only reason you know how to use Excel better is that you have past experience with it. That's, effectively, the sunken cost fallacy.
"size" - what?
"some of the external tools" - duh? But what on earth are using using "external tools" integrated to Excel for?
"size" - what?
"some of the external tools" - duh? But what on earth are using using "external tools" integrated to Excel for?