In '2 ways to create and preserve formulas with fiddler for Google Apps Script' I gave some examples of how to preserve formulas if you are using fiddler for Sheets.
Fiddler does have a number of abstracted range manipulation methods (mainly to help with formatting – see Fiddler and rangeLists) but those same methods can be used to selectively write values, thus preserving formulas in other columns.
In '2 ways to create and preserve formulas with fiddler for Google Apps Script' I gave some examples of how to preserve formulas if you are using fiddler for Sheets.
Fiddler does have a number of abstracted range manipulation methods (mainly to help with formatting – see Fiddler and rangeLists) but those same methods can be used to selectively write values, thus preserving formulas in other columns.
https://ramblings.mcpher.com/gassnippets2/fiddler-third/