Update gspread from the last row in the spreadsheet

Question

I want to update a worksheet in google by using the following code:

gc = gspread.service_account(filename='gspread_keys.json')

#open the gspread sheet 
sh = gc.open("data_horas") 

#use the worksheet 
worksheet = sh.worksheet(title="cum_data")

#get values from the existing worksheet and calculate the last row by the length of the rows.
w=worksheet.get_all_values()
w1=len(w)+1

worksheet.update(w1,[df_2.columns.values.tolist()])

The idea is to update the worksheet from the last row+1.

Question:

Could you please suggest how to update the Dataframe in the google worksheet starting from the last row and avoiding the header of that Dataframe?

Thank you!