Thomas du Crest shared some concepts done for the Mirror Dimension sequence.
Concept Artist Thomas du Crest shared the concepts done for the Mirror Dimension sequence of Spider-Man: No Way Home. The scenes are created using Blender and Photoshop and depict Spider-Man running around the city with Doctor Strange's cube.
There are also some scenes in the mall modeled by du Crest:
Thomas du Crest has worked on Spider-Man: Far From Home as well. You can also find other impressive works in his ArtStation portfolio.