STEP files before SOLIDWORKS 2024 are notorious for being difficult to work with. One of the biggest issues is that when you import a file, you've always had to import everything, even when you only want one part.

New in SOLIDWORKS 2024, STEP file importing parses apart the file you provide and allows you to select which component(s) you want to import.

This saves you from unnecessarily large files and keeps your model as simple as you need it.