OK .. I seem to be making progress.
in File Explorer:
White Tower sees Silver Tower, Lenovo, and Acer
Acer sees White Tower, Silver Tower, and Lenovo
Silver Tower sees White Tower, Lenovo and Acer
Lenovo sees White Tower, Silver Tower, Acer ... and itself
And I just realized that the OP said all four computers were on same unmanaged switch, and the two laptops aren't, they are WIFI 5g.
I have shortcuts for batch files that copy files to and from White Tower to each of the other three computers that work both ways for Silver Tower and Lenovo but not for the new Acer Laptop ... says "directory does not exist" and "network name cannot be found." I can manually click in file explorer and copy/paste to or from any computer to any other computer but can't use batch file to automate the process. Her old laptop (Lenovo) used to be able to use batch files to copy to my computer and she keeps on my to fix the brand new "broken" windows 11 computer so it can work like the old one.
So at this point I want to know why Lenovo has itself on the list of network computers and the others don't display themselves. And I want to know how fix batch files to automate what I can do manually.