Apu is a character that has evolved with the show, has had character arcs and development of that above many other characters. If you wanna just narrow it down to an "offensive stereotype", I think that's on you. Or is the unspoken issue the voice actor behind it?
Bush Senior while president thought The Simpsons were a bad depiction of Americans, He said in a speech he wanted Americans to be "a lot more like the Waltons and a lot less like the Simpsons”. Just about every character in the show is a Cartoony stereotype of something.