Does subdivision surface modifier and box modeling require retopology? This is my game character it has 30,000 vertices with a subdivision surface modifier level of 2

I tried searching up average number of vertices and polygons, where sources say that most multiplayer games that run smoothly require at most 10,000 vertices for characters

Im struggling to lower the vertex counts as lowering the subdivision modifier will ruin the look of the model

Any suggestions it would greatly help

BTW using this character for a multiplayer game with around 10 players playing at the same time
In general you'd want to retopo and create a low poly game model. That is for two reasons:


You want to animate the character. Since moving the character makes flaws in the topology very apparent retopo is necessary. The topology should allow natural movement of limbs and facial expressions.
For efficiency reasons you don't want to go way overboard with the vertex count. While hero props and characters may be high in details, you should only use real geometry were it's necessary. Everything that doesn't impact the actual shape can be compensated by textures, namely normal maps and PBR materials. This is done by "baking". You create a low poly model and bake the details from the high poly model into the texture.