For many years, the option of automated edge selection during the Solidworks has been available Roundings.

With version 2025 This possibility also exists in chamfer. It's about this, that after selecting the edges (not walls) appears belt selection tools, where you can choose from the available options. Of course you can do this, What has been automatically marked add other walls/edges/operations, etc., as well as unnecessary can be removed.

If you do not need this tool or hinders the choice – You can turn them off by distinguishing Show selection toolbar.