Immutable function on an upgradeable contract

I have an upgradeable contract but I wish to set a function that cannot be changed when upgrading the contract, is there a way to do that? I only know that immutable is used on variables but not sure if I can do that on a function.

:1234: Code to reproduce

contract UpgradeableContract is OwnableUpgradeable {
   function initialize() external initializer {}

   function changeableFunction() external {

   function unChangeableFunction() external {
       ....// can i make this function unchangeable??