@Ash2021xo my dd is 8yo, 128cm and just a smudge over 24kg, she is precariously on about the 15th percentile and as soon as she is poorly drops massively. For various reasons also has food aversion and doesn't eat so much as picks at food on her plate.
Having tried everything from shapes to food colouring mash to her favour colour that day I can assure you nothing has worked.
My honest advice is don't sweat it. He is still very young, most kids go through the beige stage. Don't make my mistake and make food a battle ground, there are some hills not worth dying on.
Until the last maybe 4-6 months dd lived on mini cheddar, jam sandwiches, 6" value pizza (the 50p ones with naff all on them) chicken nuggets, French fries and sausages. She would starve herself for days rather than eat something she didn't want. And I so mean days.
I spend hours reasoning with her that a chicken beast chunk was basically a naked chicken nugget, pork meatballs were just sausages rolled into a ball, mash is just the inside of a chip etc etc and nothing worked.
I have no idea why something suddenly clicked with her, but earlier this year we made a deal that she would try 1 new thing a week. We have for the most part kept it up and VERY slowly her repertoire is expanding.
She has eaten shepherd's pie topped with sweet potato mash tonight for the first time ever without any battle, fuss, tears, tantrums or deliberately making herself throw up in her plate so she so she have to eat it.
Her diet is still very limited but she will now eat pasta bolognase (asda smooth sauce with hidden veg is genius), fish fingers, fish cakes, roast chicken, beefburgers, peas...
As long as he is gaining height etc in proportion then my experience with dd is that they aren't bothered. I begged her specialist for help and a referral to a dietary specialist and basically got told she is healthy (blood levels wise) and is growing so she is fine in their books. It is frustrating but they do grow out of it. Show hi. Foods are safe, offer and don't make a fuss if he refuses. As he gets older and can understand reason and logic it should start to get easier