Hello senile2,
On my side, I use a PENetwork to mount a network drive.
It is defined for each profile in PENetwork.ini using PE Network Manager - Configuration/profile editor.
In Build Core, Network Options tab, use the button "Start PENetwork Configuration Editor"
Select the profile (Wireless, dynamic Ip...) then in the tab Network Drives entered the informations
Use the "+ Add" button to add the Network Drives to the profile then Save.
You can do the same on the other profiles.

For info, the custom PENetwork.ini is placed in \Custom\PENetworkini folder. Delete this folder to return to the default configuration
in PENetwork.ini you should have something like that.
NetPath=NetPath
NetDrv.Path1=\\ComputerName\SharedFolder
NetDrv.User1=xxxxx
NetDrv.Pass1=xxxxx
NetDrv.Letter1=Z:
Otherwise, you can probably use PeNetwork_AfterIP.cmd with Net Use Z: \\xxxxx written inside
For that, copy PeNetwork_AfterIP.cmd from ".\Projects\Include\x64(x86)\AdditionalFiles\Windows\System32" to ".\Custom\x64(x86)\AdditionalFiles\Windows\System32"
Edit the batch of the Custom folder (keep the Include folder intact) and in Build Core, Main Interface, enable "Add Your Custom Folder" CheckBox
In running PE, it is launched after the network configuration, once getting the IP address