In both western and eastern medieval art drawings of people are not very realistic and sometimes quite cartoony. Was this because artists lacked the tools and materials to create detailed art? Or was it because they lacked the time/motivation to learn. Or another reason.
We get similar questions pretty frequently, so here some previous answers that might be helpful:
Why do animals in Medieval manuscripts look so crazy? Did the painters not know what they looked like? Was it intentional? Did they have a hard time drawing? by u/CoeurdeLionne and sunagainstgold
Why did it take so long for artists to get to grips with perspective? by u/kastdenvaek
Why do professional paintings look photo-realistic in 1700s England yet look so awful 100-150 years earlier? by u/pipkin42
Why did pre-renaissance christian art degrade so much compared to the classical period? by u/Guckfuchs
And plenty more in the FAQ about visual arts