12 week old still not eating regular food

Help...
Hi everyone Goober is now 12 weeks old and still won't eat any other food than 2nd step KMR..
I've tried about every kitten food there is..
Can, pouch, kibble. Nothing..
His poop is runny he has been to the vet and I'm out of ideas..
Any suggestions
Help..♡♡

Was he hand raised or with a mum. Are there any human foods you have tried? Tuna bits ? We have one all 9 weeks who won't touch wet, unless it is fish and one who won't touch kibble. Is the poo runny from to much milk content do you think. Have you tried slowly mixing some pate food in like a tiny bit at a time until you get to normal food. You might waste some wet in the process but it might work ( because at frist it be only a few teaspoons and you need to throw out left over wet after a few days , so buy the tiny cans. Also warm the food with abit of hot water.

Is he drinking water?
Good luck with your kitty

Have you examined his mouth to see if anything is wrong? He may have sores or something isn't right from birth.If everything looks normal, I agree with above and mix the KMR into some food and see if he will start that way. I wouldn't worry so much about nutrition right now, just find something he will eat and go from there. Try tuna, boiled chicken, and various other soft foods and maybe withhold the KMR for a short while to see if he gets hungry enough to try something else. Keep us posted on what you find he likes!

Smush canned food down with some water or KMR to thin it out a bit for easier eating. A blob of canned food might not appeal to your kitten sinec hs's used to liquid KMR.

Thank you everyone.
I'll try some soft food with kmr.
I've tried kibble softened with kmr..
Checked his mouth and yes his poop is runny...
Ill keep you all posted.
Praying for my Goober...
Thank You ♡