If you use the internal 1.1 volt reference, as you should for any accuracy , then as the analog input is still “protected “ to 5v , you can in effect have ~60v spikes on the top of your divider and not damage the input by exceeding 5v at the input .
You can add the capacitor and possibly a lower voltage zener but check calibration for any non linearity.
( use something like 10k for the top resistor )
You can write a calibration routine in your software to take out any tolerances in resistors or the reference voltage ( map) and save the cost of a trim pot.