How to fix this mesh issue? I created an arm, and then a hand separated for it. The arm have less vertices and edges then the hand, so to connect them I had to do like this


The problem is those things in the mesh, because one vertice has a lot of edges connected to it.

Is there a way to make the hand and the arm to be more uniform, to make those things dissapear?
As Sanbaldo says, use trick to keep good topology, meaning quads as much as possible, see this site for example: https://topologyguides.com/
Here are examples of edge loops reductions:


For your hand you could try the following method, first delete vertices:

Then draw this topology: