Easy way to convert column letter to a number and column number to a letter.
Convert Column letter to number
ColumnNumber = Range(ColumnLetter & 1).Column
Convert Column number to letter
ColumnLetter = Split(Cells(1, ColumnNumber).Address, "$")(1)
Source
https://www.thespreadsheetguru.com/the-code-vault/vba-code-to-convert-column-number-to-letter-or-letter-to-number