Tessellating is to mesh the geometry for simulation. It might be slow if the mesh size is small, the goeometry is small, and the simulation volume is large. If there is a long and thin layer, the meshing can be challenge as it needs small mesh size and many tetrahedral grids. I would suggest to use larger "min edge lenegth" and "max edge length" first. Then you can add a constraint mesh for the small geometry.You may also relax the triangle quality.