Property Matrix edits the current selection. Replace Selected Actors With replaces the current selection. Both stop at the loaded level.
So when a property has to be set on every instance of a class across 240 maps, or a class swap has to run project wide while keeping transforms and matching property values, the usual answer is a throwaway Python or EUW script, plus hoping it checked out the right packages.
Level Surgeon runs that pass over every map in the project rather than the one that’s loaded. It preserves transforms, carries matching property values across a swap, and does the package checkout itself instead of leaving you to find out later which maps were read only.
Disclosure: AI authored, code and graphics. It’s a paid tool, listed at Project-Wide Level Surgeon — UE5 bulk actor editing across every map by CSAF — Core Systems Asset Factory