Hi,
You won't loose your changes. However, you won't get the potential modifications we'll add to the view file in the future. So for example, when PHP 9 is released and your hosting moves your website to it, if it has changes that breaks the code you have in that view file override, then even if you update HikaShop, you won't get the modifications in your view file override.
So in that case, you'll have to redo the changes to the new version of the view file.
So make sure you clearly write somewhere what you changed where so that the day you need to redo the view override, you can easily do it.