There is one last thing I believe I should try before crying wolf.

I have a laptop fresh from the box, with all updates and no programs installed.

Can I installed the QB2019 workstations software from the Shared folder that contains a download QB29 folder?

If not,  can you provide a link to download the correct QuickBooks Premier 2019 multi-user version product # 735-606.

I can then plug this laptop into the network and do a fresh machine test.   I'm not ruling out of there being something with the workstation, regardless of it being an I7, 16Gb, SSD system.